The Trainer #68 - Troubleshooting P0420/0430 DTCs (Catalyst Efficiency Below Threshold)
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- Опубликовано: 15 авг 2017
- Among the Top 10 Diagnostic Trouble Codes (DTCs) techs deal with on a routine basis are the “Catalytic Converter Efficiency Low” codes; the P0420s and/or P0430s.
Still, many of you are automatically swapping out the converters in an effort to resolve the DTCs. And many of you learned the hard way that these DTCs are often caused by something other than a failed converter. In fact, that's the case in most instances!
So we talked to the experts at Walker Exhaust to learn more about effectively troubleshooting these codes. Watch to learn the facts on some common myths and the 5 basic checks you can make to successfully diagnose 85%+ of these failures.
Be sure to watch this Walker video right after, too!
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AND visit their site for troubleshooting aids you can download directly:
walkerexhaust.com
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Well done, nice to find information on why it failed. Lots of cars getting CATS out there for no reason because they're not diagnosed properly and they're just throwing parts at the problem.
Thanks Pete that wss excellent information, I learned loads, cheers sandy
I kept getting a PO 420 in our 97 marquis and I figured out that it was because I had put a cooler thermostat and it was creating a richer condition than it liked so I put the oem stat back in it replaced the fan clutch which was actually the problem to begin with . I did not think that old of a car would be quite so computer sensitive . great information
Pete, always good info thankyou for sharing. cheeeeeeeeeers
New sub thanks so much I learn alot my mechanic is amazed ..
very helpful video.
2009 Acura Txs Po420 I reset the code after a week now it hasn't came back.Do I still. SHOP for a cat. conv. ?There are 2 One in the front exhaust manifold and the one before the muffler.Which one?
Hey Pete awesome video!!! Thanks for taking the time to get all this great information out to us. I like the shop vac on blow for those really small leaks we can never find. What's your thought on in cylinder pressure transducer for back pressure testing?
Excessive backpressure can be determined in a few ways with in-cylinder pressure testing one of them. What I like about this testing method, though, is the wealth of information you can get from one capture.
I checked live data on my ES300 and the rear 02 sensor readings with be in a good place and then randomly go low or high (mostly low) and don't match each other. One may stay low for 10 seconds and then bounce back to 450. This is at steady highway speeds. I can clear codes and will eventually get a P0420 or P0430 or both. The car has 200,000 miles. I runs very smoothly. I'm thinking bad downstream 02 sensors? I hear one is a real joy to change..
Conventional oxygen sensors tend to fail and not come back to life. Try a snap throttle test and see if they both react.
I wish you would have asked
The oldest biggest question of all time
Is a cat cleanable..? And how is it best done..?
Do you know...sir...?
Thank you Rick..?
VERY GOOD
LASERS can reflect off of surfaces.. a plumber taught me this, he puts masking tape on plumbing pipe to get accurate temperture.
It's not the laser reflecting off of the surface. It's called emissivity and refers to the materials effectiveness in emitting energy as thermal radiation. Emissivity is defined as the ratio of the energy radiated from a material's surface to that radiated from a blackbody (a perfect emitter) at the same temperature and wavelength and under the same viewing conditions. Black is better than shiny...
Is there any reason why a 2016 78k miles versa would be getting 2.200 b1s1 and .400-.800 b1s2? I should note code p0420 with part of the intake housing broken parts to engine compartment so small holes in intake
I'm betting that the front sensor is a Wide Band sensor and will typically show a higher voltage than a conventional sensor. The rear is almost surely a conventional sensor that sounds like it may be switching. That could indicate that the feed gasses going to the cat are incorrect OR the cat is bad. Need more info...
Motor Age what other info is needed. Code p0420 comes up too. That should be enough right?
@@priusgame1178 Not really. There are a lot of possible causes for the P0420 code. The intake leaks are likely the primary cause and should be repaired before the cat is truly damaged (if it isn't already).
@@MotorAgeMagazine Motor Age I will be replacing the damaged part of the intake housing today. My next would be to check if the cat is done I just want to see if it indeed shows in my readings. I am seeing these have a/f sensors so I took a different route in testing the readings which I hope I can learn here soon
. I am being told 9 times out of 10 p0420 is for sure a bad cat... I'm hoping to be that rare 10% with this 2016 versa how they rely on a/f sensors now
@@priusgame1178 You may want to take it to a dealer after you fix the intake. Cats are generally warrantied for much longer than the basic powertrain warranty.
Can running with slightly to much oil cause these cat efficiency codes?
It's possible if the breather system is drawing the oil into the intake.
I have a P1273 code on a 05 murano. So I hooked up the scan tool and looked at the voltage, I compared Bank 1 and Bank 2 readings,the Bank1 has.300 volts and Bank2 has .600 volts,the two readings should be the same,right ?
What are your STFT and LTFT doing?
The STFT is 0.7 %and fluctuating ,the LTFT is, -10 %
@@mckoylach1622 Both banks?
Motor Age yes,both banks...thank you
@@mckoylach1622 Can you share freeze frame data?
Last week PO420 appeared on my scanner for my service truck. I had been on a two-week job that called for lots of idling. I took the service truck for a 20-mile trip at 65 mph, erased the code, and two-hundred miles later still no engine check light.
Hi there , I changed my Catalytic converter and the exhaust Manifold going together , and I did change
the Oxygen Sensors ,both of them , I still get code P0420 !
What could be wrong ?,
Thanks .
What is the year/make/model of the car? Some cars have 2 converters; one just at the outlet of the exhaust manifold and one further downstream, but before the muffler.
Spark plugs
@@SouthernBikerTV : Sorry for late reply , i just saw your comment today , my car is Hummer H3 2008 3.7 L , my car has just 1 converter , what i did was i added an Extension to the Oxygen sensor on the down stream , so the Oxygen sensor is mounted on that Extension , that solved the problem , but i guess probably these OEM made parts may not be that compatible to our cars ?! Now i have to change the Secondary Vacuum air Pump as well , so far what is your opinion after what i said ?
Thank you .
@@honestscentz9300 : Hehehe , what ?
What Spark plugs have to do with changing a Catalytic Converter ?
My Spark Plugs are New as well .
Miss fire and lean and rich it all about a tune up the Honda dealership in Pennsylvania Diagnosis my po420.
the best catalytic converters are OEM, aftermarket ones sucks
Hello. Sir Would you happen to know anything that can cause a switching rear o2 sensor other that a bad cat? Thank you.
Sure! If the feed gasses going in are out of whack, beyond what the cat can handle, you'll see the sensor react - but usually it will stay high or low. Key is to make sure all the other variables are correct before you condemn the converter.
Thank you. I like" Usually, it will stay high or low" because if the feed gasses is rich, the o2 will be high, and low if the feed gasses is lean. Unless you have leaky injectors and a vacuum leak at the same time maybe that overwhelms the cat and force the o2 to switch or the cat is cold.
So why the hell Walker sell universal cats for ??????? Take our cash I guess.
THERE IS AN EASY, CHEAP & PERMANENT FIX, JUST INSTALL 2 SPARK PLUG NON FOULERS INTO THE O2 SENSOR BUNG AFTER THE CONVERTER AND THEN INSTALL THE O2 SENSOR INTO THE NON FOULERS. NO MORE CODES, THE CAR RUNS GREAT, & PASSES INSPECTION. I HAVE BEEN DRIVING MINE 5 YEARS NOW LIKE THAT. COST WAS LESS THAN $10 AND ONLY TOOK 10 MINUTES TO INSTALL.
HELPPPP.. Igot 420 and 430 codes. B1S1 0.300 AT IDLE 0.285 AT 3000 RPMS
B1S2 0.280 AT IDLE 0.280 AT 3000 RPMS
B2S1 0.600 AT IDLE 0.580 AT 3000 RMPS
B2S2 0.290 AT IDLE 0.310 AT 3000 RPMS ON AUTEL SCAN TOOL
Let's start at the beginning by identifying the vehicle you're working on. Make, model, year, mileage? Any other codes stored? How does it run? What are the fuel trims for both banks at idle and 2500 rpm. Are the front O2 sensors switching? Are the rear O2 sensors switching?
05 nissan frontier, v6 runs very good. no other codes stored. has 2 converters and 2 banks., one bank doesnt seem to do anything at all, it =justs stays at.285 mostly,. idle or revved it doesnt change.. the other bank, it changes
@@randy1ization There are so many tips I could share. First, make sure the O2 sensors are working properly. You can do this by performing a WOT test and see if the sensors respond. They should swing low as the throttle is slammed open and go full rich when the throttle is shut.
Ki
Cliché.
LOL. This video is no better than the rest of them. One code, and it could be FIFTY possible causes. Yeah, tear half your engine apart trying to find the problem. What the hell good is a trouble code if it doesn't tell you what's wrong? A worthless joke!
For you the easiest way is probably just keep chucking parts at it until it's fixed.
@@Johnsmith-zi9pu Guess again. Since my comment, I only had the cat replaced. Got rid of the P0430 code.
@@jakejones5736 Your lucky, it could have been a sensor fault or incorrect air fuel ratio and you would have flushed your money down the toilet.
@@Johnsmith-zi9pu Yeah. At the time, I had it in the dealer for a couple K worth of other work, so decided to have them confirm the diagnosis and replace. Even though it was in their hands, it wouldn't be the first time the DEALER has misdiagnosed... costing me money. Based on that, I have to agree, I WAS lucky!
Oh, and since they already had half the engine apart, the additional labor cost was minimal. Not to mention, due to politics, the ONLY place you can get the part is at the dealer.
Mass air flow system
Not hardly. Otherwise it would be affecting BOTH banks.