EGR P0400, P0401- P0409 Diagnosis+Understanding Pt3
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- Опубликовано: 4 сен 2024
- Diagnosis and testing of Electronic EGR valves is covered to complete this series.
Part 1 is here: • EGR P0400, P0401- P04...
Also see TPS testing for more details on testing any potentiometer: • TPS (Throttle Position...
And here is a video from my friend Eric at South Main Auto Repair that a viewer suggested has info on how to activate the EGR signal. ! • Honda Odyssey EGR Trou...
Thanks to Johnwrench4speed and South Main Auto Repair for some contributions to this video.
By the way I love how within the time I typed this I already got 2 likes. Hey, watch the video first before you judge it lol!! Or maybe it was people accidentally hitting like instead of dislike lol!!
Guys you're the best and I appreciate your support tremendously! Enjoy!
Schrodingers Box very well explained videos, thank you for sharing your knowledge with us, please throw me a 🍖, I have a 2.0 tdi engine with VVT system and 2 electronic EGR modules, from now and the I experience this engine stalls, a little bit rough idle and increase fuel consumption, but not always, only some times, usually after 3-4 days of city driving, the strange thing, NO CODES whatsoever, can a electronic EGR go partially bad without setting any codes??? Or should I look somewhere else!
You said in Part 1 that the EGR reduces fuel consumption but it is not the case, it actually increases it. As there are more exhaust gases at the intake, you would need to increase the load in the engine in order to get the same power and acceleration than with the valve closed, therefore the specific fuel consumption (litres of fuel consumed/power) will increase. The decrease in the temperature at the combustion chamber will decrease the quality at which the fuel is burned and the energy that is obtained from it, so more fuel will be needed to produce the same power. It also increases the soot production and the opacity of the exhaust gases.
Moreover, here in Europe it is very common that Diesel engines clog up the valve and intake manifolds because an oily fuel builds up much more carbon, so a lot of people just block the valve so that it does not work.
Greetings from Spain, and thank you for making one of the best automotive channels on RUclips.
I always look forward to new videos from this guy! No one on RUclips goes into so much detail - I've learnt so much. Thanks, Matt!
As you mentioned, I primarily only work on GM vehicles, but I do work on other makes/models from time to time. Great video with concise explanations on what your are doing. Keep the videos coming. I enjoy watching them, for educational purposes, and also to see your humor remarks at times. :)
Great video, Matt. Myself being a military mechanic, I can't tell you how much I agree with your trouble shoot over replace method when dealing with automotive problems. I've seen a couple mechanics go down the latter path and they don't last long. But anyways, keep up the good work! I appreciate your videos, sir.
Thanks man! Glad you appreciate them!
Man by far you're one of the best. I've been looking your videos for a couple days now, and your material has the perfect combination of theory and practical to ensure a full comprehension of how all works. Thanks for such a great material. Keep on going.
Your awesome dude. All of your videos are excellent. And your right about the numbers being through the roof if you simply stopped the video at the point you remove the EGR, but you are the difference between empowering by actually teaching/through explaination and demonstration. opossed to simply changing parts. Keep up the good work and videos, thanks.
Well said!
I humbly bow down, you're the Best teacher I've ever had 😅. You've just crammed a semester of college to a 30 minute video!
Wow, thank you!
Appologies accepted :) you remind me of a magazine writer as watching your presentation takes me back to the first five or so years of my autotech career reading Motor magazine and the diagnostic stories along with underhood service magazine while waiting for more cars to arrive on the hook with connecting rods hanging off the bottom...one of them actually had "Schrodingers Box" as a regular feature
I'll sue them!
Thanks Matt for all the insight you have given me , I'm no longer a parts swapper !!
My neighbor had been working on his 2005 sports trax, 4.0 truck if you can call it that. He had replaced just about every part he could , friends would say its this or its that, you know how it goes. So I told him to pull it into my shop and lets actually see what's wrong. Ended up being a busted intake spring on cyl 4, and I guess his friend replaced his plugs and didn't get them all due to to much hassle to get to 3 of them, removed all, regapped, they were all wrong. Now his "truck' runs great. Diagnosis first, repair 2nd.
Again thanks Matt
Perfect story, love it! Yes I certainly "know how it goes" lol. It's almost perfectly predictable ain't it?
I will say one thing about swaptrons- they always make diagnosis easier for us when we get the car because we can pretty much rule out plugs, wires, and O2 sensors lol.
You can also use a fused 9 Volt battery to open the EGR whenever you want.
Great tip on the donor connectors off engine swaps, or even if one goes to junk yards etc. which will assist in testing without back probing.
Also, what is that tool with the switch that you use when applying 12 v to test with?
I have never seen one of those. Not sure what to call it to buy one.
By far the best maintenance videos I have seen. I would rather you teach me how to fish than just feed me.
This series is excellent. '87 4Runner failed smog and the issue is with nox according to the report. I have seen other videos but nothing as comprehensive as this 3 part diagnosis series. 2 thumbs up here! Thank you for good content! Ever consider teaching at a trade school? Just a thought.
Sir you know you are always getting a thumbs up from me =) I really enjoy the direction your channel is headed in. Instead of just rocking spot on diag, you opted to educate people on the functionality of some of the major systems you will be looking into or are looking into. Given enough information about a subject, people should be able to understand it enough to get on same page with you and maybe even in the same book. The part swapper elimination plan is in full effect. Maybe you can turn the 2 percent into 20, then 40, then before you know it, the bitching about the bolt by bolt stuff is over because people are confident enough to go out there and whip out their tool set they got for Christmas 12 years ago blow the dust off of it and put a socket to a bolt. Heck ya, positive direction. Positive info. Keep up the great work.
Thanks bro, that's indeed my plan! Busted lol. If nothing else I provide the resources for those who want to adapt.
You definitely "get it" bro. Once you have this type of knowledge, you create your own methods for diagnosis, you dont follow a flow chart or someone elses steps.
Great series on EGR valves. I'm old school so could relate to the vacuum assisted EGRs, however my wife's 2007 Honda Civic was getting a major drop in idle speed her AC was engaged and the local dealer was able to "reset" her computer(there was no check engine light showing) so it ran well for 2 months. Today the dealer "reset" again but said if it happens again, we may have to replace EGR and throttle body for $1000. I'll check EGR to make sure it's clean and do the bench tests you describe. I'm a retired engineer so know my way around mechanical things but still learning the electronic "stuff" on the new technology....I miss the points, plugs and condenser changing days.
+hawaiidiver2 I don't see exactly how the EGR and Throttle body are conclusively (or even partially) indicated- what was the evidence these are the problem?
my point exactly, thanks to your EGR series, I'm smarter and my skeptical of Honda service department here in Hawaii.....in fact, my wife spent $220 in August to have what Honda calls a fuel/air induction system service which includes cleaning the throttle body. I don't see how either the throttle body or EGR could cause the issue.....BUT maybe one of those has screwed up the computer since when they "rebooted" it with their software, the problem stopped. For sure if they try to charge us for new parts if the problem resurfaces, I'll ask what their evidence is. Your EGR series helped my understand how misguided people can be with a "knee jerk" reaction to just replace parts. I need to get an auto scanner so I can check the codes if the problem happens again. Thanks again for your great site.
Paul
+hawaiidiver2 Hell man, fly me to Hawaii and i'll fix it for you lol!!
One thing I have seen many times is shops not only misdiagnosing EGR but even worse, they "fix" EGR codes by replacing ALL the components without diagnosing which one is bad. So even if you just had a bad vacuum line- they replace the valve, solenoid, diverter, checkvalves and all the lines. $1300 later, yeah, your EGR problem is probably fixed but it could have just been a bad hose.
I've seen this done on other systems too- like AIR. Si not only do they not have to know how to diagnose- they dont even have to know how the system works!! They just change everything!
Guess they would fix a leaking faucet by replacing the entire sink lol
Just found your video tonight after working on a neighbors car after it flagged two EGR codes. It is so nice to finally find a video from someone who knows what they are doing, I am sooo pissed off with the stupid threads you get from idiots who have no idea what they are doing and just speel rubbish for the sake of talking nonsense.
I am an electrical tech in a hospital here in Ireland and am used to working on all sorts of equipment, cars are something I like to tinker with too and its great to be able to find someone else who is like minded!
Keep up the good work buddy, it's very much appreciated!!
Thanks man. Your reasons for the aggravation are exactly what I have always experienced and what motivated me to create this channel!
A stuck open pintle (plunger?valve?) can cause nonstart. Thats v v interesting. My Tigra/Corsa starts/fires but cuts out. I've been chasing this for a month. My egr is different to yours. I've put 12v to the appropriate prong and battery earth likewise. No movement. I can't even really tell if the pintle is stuck (if it is!) open or closed! However this is a good lead . Thank you.
Yes u are a step above bro.
Thanks fo da extra info.
Oh and somewhat related. EGR's on most OBD-I vehicles are vacuum powered with a diaphragm. Can only use a DVOM to test the position sensor (plunger style) and VREF. You OBD-II guys have it easier with all the electronic stuff.
DJDevon3 You can use a code tester to check codes. It can show EGR % open or closed. Also on a Toyota, it shows EGR flow.
EGR's don't make no god damn sense. Loved everything about this series. Another home run from Schrodingers Box.
LOL. Really? But it's for NOx control. You know that.
Was an inside joke for Schrodingers Box.
***** I read all the comments and watch all the videos so I was actually totally getting it. Lol
...I even come back to the video to read more comments sometimes. Worth it with pro's commenting. :)
Speaking of. ..I analyzed the diagram he's put up if you want to come back and take a look. It gives insight into how some trouble codes come into existence on many vehicles.
DE Nichols I tried finding the original video where he said "that don't make no god damn sense" but couldn't find it. I want to cut that clip out and make a meme out of it. :)
Very Very helpful, first time learned about EGR valve.
AT LAST A FIX FOR MY CHEVY 4.3L VORTEX ENGINE, POSSIBLE FIX FOR YOURS!
Hi,
I have a 2000 blazer with the same problem as you and thousands of other people out there.
NO one could figure out my problem. I purchased my blazer used last year with 113,000 miles on it.
It ran great over the winter and this spring it started misfiring on cyl. 4 just like yours.
I changed everything in the ign. system just because of the age, hoping it would solve the problem. It did not.
NO big deal, plugs, plug wires, rotor, Inlet air temp. sensor, distributor cap, coil, & alternator. They needed to be replaced anyway, but what a bummer I still had a misfire on cyl. 4.
To make matters worse, I would only get the code P0304 (misfire cyl. 4) only a few times in months of driving.
No other codes came up. It would be worse on wet or low air pressure days. On dry days, or higher air pressure days, the problem would be almost nun-existent. After four or five miles of driving first thing in the morning, the misfire would go away and the engine would run great for the rest of the day even if I let it set for ten hours while at work. It only gave me a problem first thing in the morning. I would leave my house going up a hill for about a mile. The misfire would only show up around 2000 RPM when the engine would try to shift, then the misfire, and the trans. would jump from first to second in and out until I would let off of the gas and let it shift and then give it more gas. kind of like driving a standard even though this is a automatic transmission.
I asked everyone that new anything about automobiles if they had any clue of what the problem might be.
I got the same old probable cause problems that I have already tried.
I new a good scanner would help a lot but I do not own one and so many other people do not own one, so I thought I would try to find the answer with good old common sense and testing.
Four weeks or so I read and watched every video and training article that was related to my problem, and what I learned was amazing!
I found out there are thousands of people out there with the same exact problem I was having with my engine and nothing seemed to work. Knowing that, I began to realize it was not a simple, obvious problem that was addressed often.
To find this problem I knew I had to understand how all the parts worked and how to test them.
I learned how to test the sensors with a meter, so I tested every sensor on the truck I could using a vac. pump, volt/ohm meter and everything tested GOOD.
I tested the MAP sensor, Crank Case sensor, Throttle Positioning sensor, MAF sensor, Air Temp. sensor, Cam positioning sensor, EGR valve checking for 5 volt reference, correct signal voltage, and good ground.
I noticed the problem was worse on wet days even if it did not rain and the engine was dry.
I figured it must be a pressure thing because the problem was worse with wet days which equals lower air pressure.
Now with that in mind, I looked for a control that worked on air pressure and on my engine it is the MAP sensor.
I unplugged the MAP sensor and wow, it ran great with no problem at all.
Now I have already tested the MAP sensor and everything tested great. I started looking into how the MAP sensor works with my system and found it monitors the EGR valve, and sends results to the computer to help in adjusting the timing under load at certain engine conditions. I plugged back in the MAP sensor and the problem came back.
Knowing it monitors the EGR valve I decided to unplug the EGR valve and give it a go.
Behold, the truck runs great with no problems.
Of course it is running very rich and this is not a fix but a clue to the problem.
I should mention that the 2000 GM 4.3L Vortec engine uses a lineal EGR valve.
This valve has only one solenoid and uses no vacuum line connected to it.
The EGR valve has a throttle positioning sensor (potentiometer) built into the EGR to tell the computer what percentage the valve is open or closed. It is a five wire plug. One wire 12VDC, one wire 12V ground both used to operate the EGR pintle movement. One wire 5VDC reference, one wire signal wire(voltage back to computer), and last is a ground wire.
I removed the EGR valve again to double check it.
The original test I preformed on the EGR included a good cleaning of any carbon build up, cleaning and checking the pintle and seats for any build up, a 12 volt power on and off confirming pintle smooth movement, and a ohms reading on all pins confirming ohms drop on the pintal positioning sensor.
Something bothered me though, I noticed when preforming the pintal positioning sensor test.
About 1/8" of an inch of the pintal being pushed in, the ohms jumped to a reading 1K ohms lower than it should be for about 1/2 a second and then return to the correct value.
Every time I pushed the pintal in It would do it. kind of a hiccup of sorts, other than that, the EGR tested perfect.
Pushing the pintal in, the ohms started at 4.9K closed valve and drops to .57k open valve.
Valve closed= 4.9k
Pushing pintal in very slowly = 4.9k-3.8k smooth fall.
Continuing pintal inward from 3.8k it would drop instantly to 2.7k for 1/2 second and return to 3.4k and fall at a smooth rate as the pintal continued to be pushed in..
Now if this was on a good scan tool it would show up as a quick voltage drop. Still easy to miss.
Anyway, I changed the EGR and problem solved.
Truck runs like new.
I know you may have changed your EGR valve, but even new parts are bad off the shelf. It would test good, you have to move the pintal in and out very very slow and watch for the ohms to change in a smooth up and down. If it jumps around at all, there is a problem with the pintal positioning sensor and the EGR needs to be replaced.
I Got no codes for bad EGR
The only code I got was P0304 Misfire Cyl. 4
Sorry so long, hope it can help
TayloredSteam
Definitely a step above.
Great Videos...better than most professionals! Some of the corrective comments from other viewers are valid but not necessary. This was a general "course" description of the operation and testing of the EGR system ....it was not intended to be Ford specific. So as their knowledge is appreciated, it is somewhat irrelevant for general purposes.
Thanks for the compliment and comment. Yes that happens a lot and often it's just people basically looking to point out every error I make however in this case it is a valid point they bring up. In these videos, my regular viewers know I try to cover every component of a system to make a complete and thorough tutorial. Forgetting DPFE when I actually was demonstrating on a Ford is a pretty big oversight. The ones who pointed this out are regular viewers and in fact contributors to the channel and I not only give extra credibility to their opinions, but they are also right in this case.
I can't cover every single type of EGR (and I didn't- there are several other designs in much older cars using coolant temperature switches and venturi vacuum for example) but I should certainly cover the one in the car front of me lol!
Good points! I suppose I responded too quickly with a knee jerk response. I am so used to encountering "nay sayers" and people that point out things, not as a helpful tidbit but as a reason to show flaw...your explanation is spot on and again...point taken, thank you for broadening my opinion!
***** Oh trust me I know about the naysayers, Sam, and you are absolutely correct. 98% of the time when people do what you pointed out, it's not meant constructively. I even have people who sub to my channel for the express purpose of giving a thumbs down as soon as I release a video in fact. But in this rare case it's mean constructively.
Thanks for watching my back though bro, you definitely "get it" and glad you are my side!
that 5 wire connector and the objective of the valve means that that 5 pin connector is most likely a stepper motor controller which most likely includes a potentiometer that being said the potentiometer is a pot which has 3 terminals which the middle terminal measures the current resistance agents the potential resistance break it down into what it says potential meter used in applications like a volume knob or a very precise electronic control and sensing the position of a motor down to the 1/16th of a revolution very similar to what controls the speedometer or gas gauge rpm gauge
I'm with you on this. A stepper motor would give more precise control of pintle position. He says amount of pintle open position (in percentage) is controlled by pulse width modulation of solenoid coil voltage. I can't see that as possible for 1: Very difficult for solenoid to hold any steady position between power on and power off - it's going to be either full open or full closed. 2: Turning an energized (solenoid in this case) coil off releases stored energy as a stepped higher voltage BACK into computer output. (Just as an ignition coil does to spark plugs).
The use of a potentiometer suggests a stepper motor is involved - not a simple solenoid coil.
But a question I have is how to reverse pintle position? The polarity of control voltage from computer would need to be reversed (can be done).
He assumed the other EGR valve was bad because pintle was in opened position. Perhaps applying reverse voltage (in a pulsed manner to operate stepper motor) to see if pintle moves to closed position (though it actually could be stuck too).
I think he's dealing with stepper motor control. He is a pretty sharp fella though! 👍
*HEY SHRODINGERS BOX! HOPE YOU SEE THIS COMMENT*
This is my response to Tech Mechanic's post of 4 weeks ago....who brought up idea of EGR valve being controlled by a stepper motor instead of simple solenoid.
I am asking for your thoughts?
*We enjoy your videos!*
I'm with you on this. A stepper motor would give more precise control of pintle position. He says amount of pintle open position (in percentage) is controlled by pulse width modulation of solenoid coil voltage. I can't see that as possible for 1: Very difficult for solenoid to hold any steady position between power on and power off - it's going to be either full open or full closed. 2: Turning an energized (solenoid in this case) coil off releases stored energy as a stepped higher voltage BACK into computer output. (Just as an ignition coil does to spark plugs).
The use of a potentiometer suggests a stepper motor is involved - not a simple solenoid coil.
But a question I have is how to reverse pintle position? The polarity of control voltage from computer would need to be reversed (can be done).
He assumed the other EGR valve was bad because pintle was in opened position. Perhaps applying reverse voltage (in a pulsed manner to operate stepper motor) to see if pintle moves to closed position (though it actually could be stuck too).
I think he's dealing with stepper motor control. He is a pretty sharp fella though! 👍
I see your comment and it’s a really good one. man 👨 have to review this video- it’s from so long ago I don’t remember it. your reasoning sounds solid though.
Very good video. Thank you very much.
Thanks for educating.
You bet! Thanks for watching!
I paused the video and spent some time with the electrical diagram. I also wrote an article length of comment based on it and what I could assume about EGR function and android deleted it saying "unable to post" Sorry Matt, I had come comments that are really funny, but I'm not a comedian and I remember data much better than jokes. So here we go.
Taking a look at the 2 resistors associated with the the 5V reference I realized something that you later confirmed with your example of raised versus lowered resistance on 2 separate wires.
10:53 Click here for a quick link to the time the diagram and pause it to follow along.
I occasionally see engine codes with a high voltage reference on them, following this electrical diagram, I finally get how. Electricity follows the path of least resistance. When the potentiometer fails, it'll not take the electricity, the EGR sensor ground will and the PCM will know that the potentiometer is dead or missing.
So PCM's that can see high voltage on this ground probably have that additional resistor placed elsewhere similar to this electrical diagram. I wonder if Scanner Danner says at these times that some PCM's are protected by a resistor, but perhaps the true purpose is to know when a potentiometer is bad/missing.I know this because engine codes that give high voltage comments can happen when a component is entirely missing.
A note of interest that may help everyone: Dotted lines indicate that some electrical connections are not mentioned to further simplify the electrical diagram. Where we see solid lines in the electrical diagram, all electrical components/connections are shown.
Conclusion. When the 5V reference successfully gets through the EGR Pintle Position Signal wire the ECM should know accurately the position of the pintle. When it doesn't it knows, thanks to the EGR sensor ground.
Additional discussion:
Since the EGR valve control is in 12V is it safe to assume it's switched via a relay not shown in the diagram? Perhaps if the EGR is not opening such a relay could be to blame? Relays fail far less often, but successfully jumpering such a relay would activate EGR as well, so long as you don't make a mistake and fry the PCM. (I'd rather back probe the EGR.)
Side note Matt and friends:
I was sloughing my personal time for electrical diagram study to watch this video so when I saw the diagram I thought, "Opportunity!" I have a test coming up to diagnose and repair electrical/mechanical/hydraulic/and electromechanical systems in industry. It pays twice as much as an entry level automotive technician job (entry level), "Why not?" I owe all of this audience thanks in experience of thinking complex systems through even if I'm throwing myself at entirely different machines. lol
This is great information, and indeed accurate. I usually don't go into much depth on the electrical operation and theory because, mostly it's not my strength but also I know ScannerDanner generally covers that type of stuff and it's far more suited to professionals than DIY's like I focus on more. But it good to know how to read these diagrams to understand how these codes may be thrown and help focus the diagnosis appropriately.
When a sensor is monitored by the PCM it will use the 5v reference most cases. There should be a diode somewhere on the 5v circuit but I don't see it in the PCM portion of the diagram. That's beside the point though. There's a reason why the position sensor and 5v reference are connected on the same circuit through the EGR valve. It's for monitoring. Usually you could have a small 1.0v variance in either direction before you get an overvolt or undervolt error. Also depends on unresponsive time such as 20 seconds of no response before a code is set. Some vehicles have timed triggers. Unless your quick as a flash in your diagnostics then waiting 20 seconds won't be a problem.
It depends on what year of OBD-II and car manufacturer if a sensor or reference voltage are separate or bundled together as a VREF failure. Newer systems will pinpoint either over or under (separate codes) but early versions of OBD-II like 96/97 and especially OBD-I (pre-'96) could set it as a generic VREF code. All depends on the sensor design, manufacturer/year/make/model, and OBD-II CAN capability.
The relay is not to blame in this situation as he clearly shows the pintel getting randomly stuck. It's all cut and dry in this case. For the purpose of a hypothetical you bring up a good scenario where a relay should be checked (if applicable). EGR valves can have EGR solenoids (vent and vacuum) which can go completely unmonitored and contribute to a faulty flow code but not a voltage specific code so there could be multiple solenoids or relays to check as well depending on system design. Knowing how to read wiring diagrams can be critically important in situations where variables seem to come out of the woodwork and it's usually just getting acquainted with whatever system design you're working with.
when I went to clean my EGR Valve , upon disassembling the throttle body assembly I noticed that the previous person that worked on this F-250 broke off the head of the rear mounting bolt . Could this leak at the gasket have caused the P0401 Code ?
+Robert Woolridge Indeed it could
nice series man. thank you
HI Matt. First I want to say that your videos changed the way I think
about automotive concepts, you are doing amazing job. Sorry on my
English I am Serbian, so I do make more mistakes. Second because i have
same problem EGR, based on your videos I found the way to know witch
wire is SIGNAL, Ref VOLTAGE and Senc ground, by testing resistance in
between . Ref to ground no change if I move pin, Ref to Signal decrease
and Signal to ground Increase. Of corse 12v power to ground continuity.
I think its good idea to test all potentiometers like that. Tel me what do you think.
Its just idea. I am on both channels, I am a big fan. Keep up with good work
That's how i do it too! I call it "mapping" a system.
I am jus diy and my car is 1.0 l Corsa, three cylinders. dont make fun of me, its a slow, very slow car. All the best
Drazen Vulovic I'd say you are faster than the car lol.
Will be looking forward to the next video.
Me too- I hope the next car I get is a Ford so I can do DFPE sensor and complete the series right.
Good series. On your upcoming (or future NOx emissions diagnosis) here is some information regarding common causes of high NOx emissions (even though you probably already have this info):
- Over advanced initial ignition timing
- Over advancing or prematurely advancing ignition timing
- Decreased or no EGR flow
- Combustion chamber carbon deposits
- Inefficient engine cooling
- Lean mixture
- Lower octane fuel
- Low fuel pressure
- Fuel contaminated with water
- Faulty fuel injector
- O 2 sensor contaminated or responding to a false rich condition or lazy switching
- Higher intake air temperature
- Vacuum leak
- Head gasket leak
- Timing belt slippage
- Faulty input sensor
- Faulty output sensor
- Restricted exhaust system
- Low engine oil level
- Brake drag
- Drag from drivetrain excessive
- Faulty wheel bearings
- Faulty catalytic converter
P.S. To get a high NOx emitting engine to pass an ASM (acceleration simulation mode) test, a cheap fix ("mechanic in a can"), believe it or not, is adding high octane fuel to the fuel system (where I live 100 octane unleaded racing gas is available), or an octane booster, as a quick fix to minimize detonation and thereby reduce NOx (Note: This has worked for me, however, this may not be a fix in every situation).
All your videos are fantastic! Extremely helpful!
If I have performed all the tests you have described and have determined that the PCM is not sending the signal to the EGR, does that mean I need a new PCM or is this something that can be repaired? The code was P0401. EGR valve is good and working, passages are clear, vehicle stalls when valve is actuated at idle. Its the exact same valve as in the video. 1997 Chevy K1500 with the 5.7l.
If you have conditions for the operation of EGR and no signal from the PCM it can only mean the PCM is failing. But make sure there is command from PCM first, and no signal.
Matt, I think the position sensor is not working on my valve, when I connect my ohm meter to the leads and push on the pintle I don't get any changing values. I tried from the 5v reference to the sensor wire, and then then from the ground to the sensor wire. The valve is new so I didn't try this at first, but I don't know what else to look at now. I'm still getting the P0401 insufficient egr flow. I thought maybe the valve was bad, so I bought a new one from the autoparts store and tested it also, but getting the same result. What are your thoughts on this?
Very much enjoyed this episode thank you.
Great videos - thank you for making them available - the one thing you do through is scare me about destroying computer on the car if I happen to test some connectors the wrong way -
Yes that can happen for sure.
Smarty pants steve
Dear Sir. Great Stuff. Could you please advise why the throttle solenoid heats up to a point and then shuts the engine down. What is causing the heating. Nissan Almera 2002 model, 1.6.
can you tell what kind of scanner you are using
Autoenginuity.
I am also without an OBD1 scan tool or any other like your Enginuity one, But I am trying to get KOEO and KOER codes with the jumper wire method. Known result is code 33 EGR opening not detected during KOEO check. I will need to do further checks to get the total picture. Until then, I will disconnect the EGR to check for blockage and if the pintle opens or closes.
Great video. Great information keep up the good work
Ok
i love all your stuff matt let's go out side the epa box cheap gluttins adding wood alccohate and farm waste to fossil fuel too boost octain now my EGR valve is stuck like chuck! and all your vaccumie lines are dry rott'n valcanized rubber can't even HELLP! re-church ! B.F.GOODRICH! BOY DID HE GET BF.'D!
Thanks for all the info but I have a 2001 ford escape and have a code po4o1 and went thru the steps and when I put vac on EGR engine did not stall pulled EGR and cleaned port and tried again seams like no exhaust coming from exhaust tube would that large tube be clogged, fuel mileage got real bad what next.
Some ford have positive pressure EGR and the vacuum doesn’t operate like seen in the video.
I have a p1442 signal to high i just change a mont the egr and still doesnt go what to do please
hi matt...first of all let me thank you for your series of video's....so additive, think I have watched everyone so far...I have a questions though...Firstly...on EGR if the manual type is controlled by a solenoid that is vented to atmosphere when in the off position,would this not cause a lean condition like a vacuem leak and secondly ive noticed when filming you never look directly at the camera...when your filming what or who are you looking at..and finaly are you still making new videos as I notice all these are a aprox 2yrs old,are the new ones on your pay channel as I haven't subscribed there yet...how many vids are there?.Keep up the good work
I have a 2006 chevy truck with a 4.3L engine. I know that the egr valve should be on the front of the engine. On my truck there is nothing there. I've looked everywhere and cant find a egr valve. Does this truck have a different egr system. I would appreciate any information you could give me cuz I am stumped. Thanks
If it had VVT then EGR is controlled through the exhaust timing.
Hi Matt, I have a '98 Pontiac Trans-Am Formula 5.7 with this EGR system and a supercharger that keeps giving engine lights and PO4 codes. Having trouble finding a repair person can you recommend anyone near Chicago, IL or where are you located maybe I can come to you?
Sorry I am in denver.
9.23 you have 246k subs. That's pretty close to 250k subs
Yes I plan to do a 250K sub special video soon!!
Top man good explanation
Schrodingers Box . Question. When you enabled the egr by 80%, I noticed that you DVOM was momentarily reading around 6.5 volts. Is that a pulsed signal and the meter is showing the average, or is that a constant steady DC voltage? I have a strong feeling that it is a pulse. Forgive me if you actually mentioned it and I missed it.
That's correct- you're seeing an average from a PWM control.
Finally, I understand about the EGR system. Once again, it took a few tries but I think I'm almost up to speed. Just one question: would I be correct in deducing that any system with an EGR would also have to have a MAP sensor and not a MAF-only setup?
Good question. The answer is no- you do not necessarily need a MAP with EGR. I assume your question is based on validation of the EGR operation by the MAP and There are other ways to validate EGR operation other than with a MAP and I failed to mention this in the video. For example Fords use a system that basically detects there is flow from the EGR by comparing the EGR outlet to a non-egr outlet and comparing pressures (DPFE).
I’m trying to think though if I have ever seen an engine without a MAP. I have seen many engines that are MAP only and most are MAP and MAF but I don’t think that I have ever seen a MAF only engine. But even so- the MAP isn’t the only means for EGR validation or even for engine calibration with EGR operation- there are other methods besides using MAP.
@@SchrodingersBox Thank you very much for taking the time to answer this query so thoroughly. Yes, you're right - I was basing my question on how the PCM might monitor the airflow caused by the EGR. Because your videos are so engaging, they sometimes raise as many questions as they answer. This, of course, is a good thing, as it proves the advancement of knowledge. Still the best on RUclips.
Thanks for the very helpful series! I tested my electronic egr on my 2015 Subaru Outback/Legacy that is throwing codes. I got the 5V reference. But my 12v constant is only showing 4.16v. I checked the relay but that’s not faulty. Is the only option after that the Control Module?? Thanks!
that’s weird. if the 12V on that model comes from the module then yes you have to see if you have 12V coming out of the module. however keep in mind if you have some type of shirt to ground it may mislead you because you would see the voltage drop on the whole wire. make sure there is no continuity to ground if you do find there is still 4V from module
@@SchrodingersBox thank you! I think I found a wiring diagram that shows it going direct from the positive on the battery through the main relay. Not through the control module. I replace that relay, but no difference. So I’m thinking possibly the wire is deteriorating and loosing voltage. I have it with an auto-electrician now. I hope they can make some sense of it!
thanks for your knowlege video.i have question how and where can i find this scanner u r using ?
DPFE sensor and hoses is a issue on a lot of fords . Hope ya caught your flight ok.
Lol I did indeed. Yeah I totally feel bad about dropping the ball on the DPFE. I think what I will do is make a Part 4 and it will just cover DPFE, that way it makes this series complete and comprehensive to most common OBD2 EGR systems.
Thought I would check in to see what's new ...
Welcome back!! We have so much new I cant even list it!!
@@SchrodingersBox hoping you and your family is doing well these days.... And keep up with the good work you are teaching use ... And a merry Christmas as well....
wonder if you can lube the stuck thingy, with some brake cleaner and some lube afterward. "just to have a good example one if nothing else" probably just carbon buildup sticking it.
Yeah that EGR is from months ago, at the time i tried to lube it up and decarbonize it but it just didnt free up enough to work consistently. I held onto it in case I did an EGR video and needed an example lol
I'm tearing my hairs out over a P0401 on my 08 BMW X5 3.0d...
The EGR valve works and the solenoid is new. Vacuum hoses all fine. Manually keeping the valve open gives a P0402, so there is good exhaust flow through the EGR. So I'm wondering if there could be a signal problem somewhere? Can't seem to find any info on the type of feedback mechanism which was used (eg DPFE).
Any help would be much appreciated!
Thanks for the great videos!
I would start by validating the EGR flow with MAP response.
@@SchrodingersBox Thanks you for your help. Found the culprit. The new pressure converter solenoid valve is not working according to the original specs and the ECU would cut its power after a few seconds.
thank you that's video very helpful
Well Done Matt , big fan of Eric O channel - nice of you to share - See if you can get your hands on some radioisotope - great for cleaning a EGR pintle :)
Radioisotopes are my life bro. 32-P, 35-S, 3-H, and my least favorite 18-F.
Fantastic- glad you have access to some of the finest. If you need anything stronger to clean the EGR let me know I got lots of Uranium oxide concentrate. Might be a problem shipping some to you by USPS.
Steve Rob Actually, I had some uranium but my cat ate it. Thought it would kill him for sure but now he has 18 half lives.
Ha - That's What You Get If You Eat Uranium-Atomic-ache.
Steve Rob Hahaha... well an antacid should be the curie for that. This is rad, man, but I'd rather be fission.
what kind of scan tool are you using to command the egr, thanks.
Another excellent video. I think you're right that a scope would make testing these types of sensors very easy as you can directly see the output signal although in this case using the scan tool worked pretty well. Have you thought about which scope would be best for automotive work? I have a number of regular oscilloscopes for electronics work but I've been thinking about getting a portable automotive type for this type of testing. Any thoughts on the best types?
Yeah I have talked with some electronics engineers who sub to my channel and I've conclusively decided to go "all out" and get a Picoscope 4423. It would be easily my most expensive single equipment investment by far for my weekend warrior thing, but at this stage with where I am at, I think it's justified. I never thought I would need one but it would greatly fill limitations with my scantool and it would really have been nice to have one during my IAC diagnosis on my T/A since you can't test stepper motors with a DVOM and my scantool didn't have PIDs I needed.
Schrodingers Box
The looks like a good choice. With a few additional items like perhaps hi and low current clamps and a pressure transducer there's no end to the amount of diagnostics that you could do.
Schrodingers Box since your buying them I'll take one too lol. I'll be jealous. great vid.
Hi...very educational video.... I have a 1999 MBenz V6 W202... I was able to take out the EGR valve and cleaned it thoroughly.
Should the diaphragm valve be easily moved/compress by fingers to open position? I notice that it hold vacuum but when you release it does not go all the way close position... kindly assist.
Also can we do a "SRS troubleshoot" on your next video?
I have not seen one that doesn't close all the way but if your car is not idling correctly and you have 100% correlated this to EGR a faulty valve is indicated.
I'm afraid that's the case because after clearing the code P0400 and driving for 30 miles, the engine light indicator went on again.
P0400 again. Although the car runs better with responsive throttle on gasoline.
I really thought that after replacing the worn out (holes) vacuum hoses & cleaning the EGR, I was home free...
I will take out EGR unit again (a pain since it is at the back of engine for a 1999 Mbenz W202 V6 engine ( i found out that it has twelve (12) sparks plug as well)
But before doing it I will follow the steps in your video.
1) Vacuum test
2)
I have tested per your video the ff:
1) EGR valve holds vacuum but when you release the vacuum there is no sudden clicking sound telling you that the valve is closed but you could see the diaphragm slowly closing
2) Tested the EGR solenoid and directly to the battery + / - terminal and you could hear the click clicking sound
3) Tested also the plug with voltmeter as shown on your video and it does have 12v.
My plan of action (unless you have further advice)
Order an EGR (solenoid/valve in one unit) w/ gasket and do the test again before putting it in the engine?
thank you for your reply
(p.s. the car is in the garage for two weeks now & thy wife is getting you know because her car is parked outside and it has been hot out here in So. Cali) help
did you ever get to explain dpfe sensors? if so what video? my pressure feedback hoses keep over heating and cracking, even with hoses rated for 212F
Dang forgot all about that. I’d probably start your case by measuring your backpressure.
Good vid. I still can't get the clip off of the egr valve (after 20 minutes of trying) and now I have a blister. #fail Should I take plyers to the clip? Am curious are you in ME?
Just remove the clip with pliers.
Well done, bud! I learned a lot in a short time. Appreciated! I have a good question, from where do you get the electric diagrams for the different auto parts? Also, what is the software you are using on your computer to read and command the PCM? Is it opensource software? I am interested in connecting my laptop to my car's PCM and start doing measurements. Kindly if you have a video about Softwares used in automotive and how to connect your computer to the PCM, please share a link. If you do not have one think about making one, this will be so valuable. Thank you!
I get the wiring diagrams from Alldata DIY and the software I use is Autoenginuity. Thanks for watching.
Thanks for your reply!
Awesome
From curiosity i decide to try this on Peugeot 407 2.0 HDI Electronic EGR . It has 5 pins from the solenoid like in the video shown , but when i start to move the valve only 2 of the pins react to that . I put it on Ohm scale on the multimeter , but it start to behave very strange when i began to move the valve . It goes from + to - , like a was moving the polarity . Tried all the combinations but still nothing similar like in the video . Didn't have luck with finding electrical schematics for it :(
P.S. Great videos !
+r3s1s74nc3 Putting 12V to the wrong pins would most likely damage the valve position sensing- I hope you only put 12V to what you confirmed to be the solenoid.
+Schrodingers Box I was extra careful to not put any 12 V to any of the pins . I decide to try move the valve , even a little , with 3.7 V battery , but i guess it wasn't enough . Still , i guess this kind of testing doesn't not cover every electrical EGR . Any idea how can I find out witch are the 12 V supply and ground wire ?
r3s1s74nc3 Your system is a duty cycle based system so the method I showed does work on your EGR system. You cannot move it "just a little" with less voltage.
I really am going to suggest you stop messing with your EGR valve- if you don't understand basic automotive electrical you really risk damaging the system and even your PCM when you plug it back in. This is really not something a beginner should be messing with.
I have a 2018 nissan frontier 2.5 4cyc ,13000 miles no codes starts ok runs good but the pvc seems to be spiting oil , help ,
most likely valve cover.
@@SchrodingersBox thank u for ur reply. I wish i could sent u pic of the problem so the maybe u could better stand the problem. Anyway here I go in trying to describe situation a bit better. 2018 nissan frontier 2.5 L 4cyc 13000 miles. No start problems, No run problems, No codes , some oil on the air filter !!!! (1) No oil coming out the valve cover sealant or any other place on the motor. (2) at the pcv valve which is connected with a hose to the throttle body. ( it's like carburetor on a old car. ) the hose looks OK but where it connect to the throttle oil seems to be spiting out some . Thank u for ur reply !!!!! Now u did reply to me stating valve cover problem. Now since there is suppose to be proper air flow thru out the engine and not alot of suckion to the point that bring some oil out from valve cover thru the pvc valve to carburetor.
Now could u please respond to this help. or guide me to video u make on this condition on this
250000 subscribers!
Yes thanks for noticing!!! Huge milestone!!
I have a chevy with duramax LLY engine and I replaced the EGR and now the code is P0402 EGR STUCK OPEN,What happen when the electronic EGR valve stuck open? thanks for your grat videos
The engine works good, has power and looks good, But I have the code P0402
+oscar guti If it is stuck open and not clogged with carbon and does not react to 12V directly to it, you have a bad EGR and must change it.
+Schrodingers Box Thanks, I will get a new EGR valve, you are realy good explaining how to do troubleshooting and understanding how the parts work, I do airconditioning and I understand how sensors work but you video help me to know how the EGR work, thanks again
Is it possible that carbon buildup in my fully electronic EGR valve is causing symptoms similar to a small vacuum leak, measured in LTFT, at idle? Can I test the EGR valve closure with a vacuum gauge?
You would be measuring lean at idle if that were the case and idle would be rough
I seldom use vacuum gauge but it seems reasonable vacuum would be higher than normal at idle but how to tie that to the EGR? only way I can think would be to block EGR but at that point just look at the valve and see if it's open, right?
I'll pull it this weekend and take a look at the pintle position. Already checked for vacuum leaks using a full tank of propane and also did a full injector balance test looking for maybe a gummed up injector or two. No joy.
Have not pulled egr yet. New gaskets coming. Will update here on carbon buildup and operation.
Like the chanel very informative.
Could you please make review on scann program autuenguity that you use i was looking in to it in the past but is this program as good as advertised?
It is as good as advertised. I do have a video on it but it is on my pay channel which will be up soon.
Have you ever tried freeing off a stuck egr/solinoid by soaking in caustic soda or an alkaline cleaner?
Nope- I free them with a screwdriver or pick tool.
do you need to buy licences every year with you scan tool like a snap-on ?
ONLY if you want the new updates. Otherwise the instrument is essentially “frozen in time” as of the last update done.
Thanks for info@@SchrodingersBox
again thank you
$15 for that heat gun you have hanging on the wall in the background is too good to pass up. I have one of my own :)
Man, I always am amazed at when people point out the most obscure details in the background.
So actually, that heat gun was on sale for $10 (which meant I got 2 free flashlights one of which I used in part 1 of this series that someone pointed out.) True story here: As soon as I got home I plugged it in and within 2 seconds it just puffed into a ball of smoke and died. I am not exaggerating!! I returned it next day and they replaced it with the one on the wall which is an upgraded model that I have used occasionally without incident.
Could a po401 cause a hesitation under load or a intermediate rough idle?
it could. or could t. depends on cause.
I would like to know where the EGR valve is in a 2005 KIA OPTIMA
+Myron Lasch Between the exhaust and intake
Great video SB! Did you ever make a DPFE Video?
Not yet- I have yet to come across another car with one. If I do and I have time I will definitely do that.
👍
@9:09 Ha! Welcome to my world..... :-)
Matt Is AutoTap still available? I thought I saw on a web page that Autotap in not sold to the public anymore. Anyone one know for sure?
Autotap is long discontinued, unfortunately and they no longer support the product but it's still my favorite PC based tool.
thanks
What is the main function of the EGR valve? (THANKS)
in case you missed it at the start of this video, it is to reduce NOx emissions. It also adds a bit to fuel economy.
Ok I viewed the video again, so the computer takes the signal from the EGR valve.In my understanding if I'm not mistaken the signal from the EGR valve only tells the computer the opening and closing position of the EGR valve, but still I don't understand who gives the EGR valve's main coil the signal time to open and close. (THANKS AGAIN)
HHOhybridBuilder Yeah I see what you are saying. I normally avoid the specific "engineering" of designs (in this case, stepper motor) but basically it works as follows:
The computer puts out a command, seen on a scan tool as "desired EGR position". Say it's 50%. Through the 12V feed, a duty cycle is commanded to open the EGR valve. Of course the 12V feed simply opens the valve, it does not "know" how much to open it. As it opens, the 5V signaling shown in the video will feed back to the computer so the computer knows when the desired position is reached. It then maintains that specific duty cycle hold the position until another command is given to change the position and it all happens again. In the case of closing the valve, the 12V shuts off (zero% duty cycle).
The confusion comes I think, for people who like you do indeed see the basic concepts, with the fact that not all systems similar to this have *actual* position sensing. For example you may be thinking in terms of an IAC where there is similar command but not actual position sensing like in a EGR. When you see IAC position on a scantool for IAC, this is not actually from the IAC reporting the actual position based on a feedback like EGR does. It is an "assumed" position based on a command from the computer to open or close a certain amount and it is assumed to have done so correctly (my trans am IAC problem video shows this clearly). So you can see, it is critical to know whether data from the scantool is reporting a "command" and the command is assumed to be executed correctly, or if it is reporting an actual position based on a feedback. With an EGR you often get both on most systems and it's important to know which one your scantool is reporting (commanded or actual). On IAC you generally just get a commanded/assumed position but no actual validation of the position. Usually you can tell if there is actual position sensing on a component because the component has a potentiometer (e.g. 5V, signal, ground system as shown).
I hope that makes sense. It's a great question and I hope this answers your question because it's a really good question and a critical concept to accurate diagnosis.
Thank you very much Sir for the answer, very well explained. The only reason why I ask so many questions about the EGR, were because I have myself a 2002 civic with a non sufficient EGR flow, considering the passages and ports are clear from carbon deposits, but as what you did showed on your video on how to test an EGR, I haven't done it yet. This summer when it gets hot I will perform all the tests I learned from you and hopefully my civic will pass the emission test. Again Thank You So Much Sir.
HHOhybridBuilder My pleasure, you definitely got the knowledge needed to properly diagnose it now.
and how much it is going to cust
+Mahdi Joumazadeh Autoenginuity. $400-$1200 depending on features
24:42
Ford engineers just had to bury the egr valve in the fusions. Dammmmmmn it
Ford/Mazda 😂💪
These EGR codes seem to be TOO common. They need to improve parts like factory recalls. Owners need to do class-action lawsuits against car makers.
how i activate the egr vave without a scan tool
Am I color blind or are you wearing a lavender dress shirt? Man, if so, we gotz a P.I.M.P in da hood!
Hahahaha, I was literally on the way to the airport for a business trip and I got a text saying my flight was delayed an hour and a half. I figured hell how am I gonna kill an hour so I figure I'll try to crank a vid out to finish the series. Also, with 12K subs now- hey, gotta act the part you know lol!
Schrodingers Box Regular uptown mechanic now haha
Schrodingers Box I bet you were getting cat called and probably got a free coffee out of it. Nice upgrade on the DVOM by the way.
jarin wilson Hahaha yes in fact the whole time at the airport I was cat-called and hit on and got free coffee and all that stuff. It was so annoying, because I wasn't interested and wanted to be left alone but he was persistent.
Schrodingers Box He? LMAO Hopefully you did not get a cavity search.
Sharp dressed man.. :-)
Every girl's crazy! But that has nothing to do with sharp dressed men. Literally, every girl's crazy.
AutoTap is discontinued
Ну а теперь то же самое ,только по-русски!
No idea what this says but I hope its good.
show as how to turbo set-up engine you will have tens of thousends subscribends
Why?
Your a staircase above that
and after he was DEAD!