You Wont BELIEVE Why this Mazda Stalls Out!! (Part 1)
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- Опубликовано: 16 июн 2024
- Grab some popcorn, we have a CRAZY Mazda to diagnose!
Customer complaint: Dash is a Christmas Tree!
ABS, BRAKE, TRAC and other warning lights intermittently come on when you're driving down the road.
DEALER DIAGNOSIS: Replace the ABS Module for $1000!?
Well the customer opted to get a used one installed at this independent shop and guess what...it's still doing the SAME THING!
Let's gather some data and see if there is a cause-and-effect of when the warning lights come on. Weirdly enough, turning on the headlights instantly causes a Christmas Tree, and better yet, the High Beams completely STALL the car!! CRAZY!!
THINK TOOL PROS:
www.amazon.com/dp/B08XXWHQVJ?...
Enjoy!
Ivan 
Авто/Мото
Ivan's dictionary- Wicked cool-customer-oh my god.
See also DaddyBean's dictionary, "absolutely fascinating"
I had a similar issue with a vehicle a few years back. It was one of my first real diags. You would hit the brakes and the car stalled. It ended up being the ground for the main relay. It went to 3 shops and noone could figure it out I was so proud lol. I focused on the easiest circuit, brake pedal and worked from there. It was doing so crazy stuff. If you hit the blinker the radio would cut in and out. I think the wipers had a mind of it's own. I diagnose alot of cars nowadays and cant remember what I did last week but I remember the ones from 5 years ago lol.
That's my guess, or an aftermarket electronics botch job - radio, alarm, trailer brake, GPS tracker etc. Whatever it is, it's affecting the CAN network
So what was the problem!!
@@Walczyk it was a bad ground to the main relay. So when turning on the key the voltage was basically finding other ways to ground because its path was not accessible.
@@lovetolearn5253 that's a real tricky one; I had a volvo 940 and in reverse the left turn signal would come on but not blink, and the rear brake lights would stay dimly on. I thought it was a ground fault, but it finally turned out to be a missing fog light relay!
Kind of crazy. Seeing that all these things happen on current draw. I would disconnect the alternator and see if I'm getting some kind of interference from it. You did show a new alternator had been installed. But we don't know when all these problems started. When I was troubleshooting machinery, I would always go back to what others have touched to verify if the repair they made is working correctly. That's what I would do.. I may be wrong, but at least I will eliminate that one item.
The next test for me is a test of my patience waiting for part 2.
My next step is to wait for part two. Mechanical stuff I understand. Electrical is why I'm here. This stuff both baffles and amazes me.
I got burned questimating about Keith’s truck, I’ll just wait for part II. 🤔
I did too.
Same here Kerry. I have a little better than basic electrical skills in automotive. Access to wiring diagrams would also be a big help. (Subscriptions are available)
I would have chased the battery voltage code to the ABS to start. This may lead to chafed harness effecting other circuits. However, there’s a reason why I stopped being a mechanic 30 years ago!
Yup, check power/ground at ABS module while testing headlights.
Disconnect abs first ?
@@nickmalone3143 that would rule out it potentially putting high voltage on the CAN bus when the brakes are hit, for sure.
Looking forward to the fix on this one
I work Mazdas all the time. The word got out that I’ll work on them and you know word of mouth!!
One day I’ll get the same problem.. Only time will tell!!
I love it when you take your time and zoom in on wiring, explain things, etc
Thanks for all the awesome information. Big thanks, my thinktool pros in in route to my place. I know enough that you cannot show the entire process for a diag. But the information you do show is amazing
My initial suspect was a backfeeding voltage from the brake lights into the ABS and/or BCM, I always learn new methods of diagnostics and fault finding processes to take out into the field, great job Ivan 👍👍
I would check the ZOOM ZOOM box. There is no ZOOM ZOOM in this Mazda at the moment.
I had a similar problem when I worked at a dealership back in the mid 70's the dash lights went crazy.
It was a bad tail light bulb.
This probably isn't your problem but I had to mention it.
I enjoy your videos!
Unreal diagnosis!! Moving that switch makes it unhappy!! Wow, that's fun to watch how that communication network acts together!! I've never seen it like that!! Cool video!! Many thumbs up!
Thank you Ivan. Great Video. Thumbs up
Quite an interesting predicament Ivan, looking forward to the subsequent videos where you share which component is the culprit and what fix you've done. Cheers!
Its truly amazing. Older cars never had these electronic problems because they didn't have them, just the mechanical feature such as brakes, throttle, ignition wires etc. Older cars had no problem unless a mechanical issue became weak or failed and then real physical symptoms were the warnings. With computer vehicles, it's rarely a mechanical item that is failing, it's usually those sensors, probes, modules, wiring connections etc. that are supposed to be monitoring the mechanical features that fail first. Such B.S. They ought to build cars two ways, one option with engine/transmission computers only and if the customer wants to drive a computer controlled car, they can order it with all of this hardware/software that always seems to need repaired itself. I really think these are just test vehicles they are selling us the public to iron out issues in preparation for Self Driving vehicles one day. No thank you.
exactly! I own a 2011 Cruze and a 1990 S10. Guess which one didn't give me as many problems... The S10. I'd take old-school simplicity over a bunch of bells and whistles reliant on electronics ANYDAY.
Well Ivan, you have me engaged. New battery, altenator, ABS module. If you don't find the problem the whole dang car will have been replaced. Looking forward to Part II. Thanks for Sharing!
Moisture and body modules in Mazda make crazy things happen. I have had success just cleaning them
Dealer recommends to replace headlights.
Only strange issue I had was on a 1970s Fiat 124T, turning head lights on increased engine speed by 50 or so revs, voltage regulator was draining battery, but still did it after new regulator.
Love these problems, from my armchair of course.
Great work and video Ivan.
Thanks for sharing.
Very excited for part 2
Hey Ivan. Been watching your vids for a while now. You should make a top 5 make and model or just makes that you would recommend to buy used? Good stuff as always
Are you using the iCarsoft CR Ultra Diagnostics tool? Thanks for smashing videos.
Love it. This is fun. AS long as I don't have to figure it out. Is there any way to figure out which module is causing a problem. Why doesn't the initial scan and module tree show it?
My next three steps are to unplug the headlights, front corner lights, and rear lights, testing on each step. If the problem remains, it isn't related to the current draw from those lights.
Had a very similar situation with my 2014 Mazda 3 skyactiv (after changing the battery) I was able to fix it by disconnecting the new battery and reconnecting it in the morning. It's been a year since and all is well.
thorny problems seem like a trip to to comedy club for you Ivan. thst's healthy
Still seems like a bad ground, the CAN bias voltage going up kinda points to a ground somewhere going up about a volt. I'd bypass the headlight relay to see if the current is making the modules crazy.
One thing not mentioned - how well do the lights work? Are the headlights normal brightness? That's a "no effort" clue.
What happened to the check of power to the fbcm (1a, 1b)? Hazards recreate issue as high beams and acceleration. I'd suspect a wire issue caused by recent installs (abs, alternator).
You got it bro. Seems like the headlights load that ground, causing FBCM and other modules to malfunction. ABS reports an undervoltage, so there must be a poor contact somewhere. When driving, vibrations cause the poor connection to temporarily lose contact at all, thus the christmas tree even without headlights on. That's my guess.
I'm just on the minute 4 of the video but when weird electrical things happen, I think it's worth it to check quickly the battery connections and grounds that you can see in the engine bay.
Yep.
My first step would be measure voltage between the engine and the body. Seems anything that tries to pass current through a body ground causes probs. The check is faster than hooking up a bung of fancy gear.
@T.J. Kong That's funny!
So Ivan you mention that the Module acts as a pass through for the others, so disconnecting it breaks most of the network....
If the module is just passively connecting the network wires internally, could you use jumpers to reconnect them with the module unplugged to at least get some functions back so you can test drive it properly with the offending module unplugged? If you can, that'd be my next step.
Exactly what I was thinking
That and testing / visual inspection grounds
Came here to say this
Was about to post this as soon as I heard network pass though. I feel that test will work as long as it truly is such. If it acts as a gateway the test won’t work.
I agree with that approach, however, ideally, if you could go to a junk yard and get a cheap module and try it, then that would be conceptually the simplest thing to do.
it depends on if one of the terminating resisters resides in there
What puzzles me quite a lot: Since early 2000's, practically all CAN line driver ICs do work with bias voltage pulled off at least 30V from the normal 2.5V. By "work" I really mean the communication not being affected at all. And "practically all" I mean all post-200x from major IC makers like NXP, Infineon, ON, Renesas, ST,... The datasheets explicitely guarantees +/-12V, but the devices would never pass conformance tests and got accepted by any OEM's unless they really are able to work over the whole +/-30V range in real life.
Yet here just barely 1V shift and everything looks like the data is completely messed up. A bad ground should mess up just the modules connected to that bad ground (with a battery undervoltage), but the rest should in theory communicate well. But it does not.
The one thing that may explain communication loss is a short circuit of the CAN somewhere. When too far off, the lines become driven only on one of the lines and with the EMC filters it may cause such overshoots seen when some lights are on.
Good point. The whole point of the two data lines is to cancel out any bias or common mode noise. I'm thinking the under voltage on the affected module causes it to spit out trash. The jump in bias may not be the problem, but it's clearly a symptom and a clue that should be looked at.
@@HouseCallAutoRepair We're on the same page. The bias should be ignored (but having the bias change isn't normal either). I think the bad ground on the ABS caused it to spit out trash that messed up the network. We weren't decoding any packets, so we don't know if they were good or not.
I would have done a careful visual check, then looked into the ABS powers, grounds and signals. Since ABS is on HS Can, disconnecting it's connectors and using jumper wires to bypass the module on the HS Can then watch the Can system. On to part 2.
For years, GM has used star washers in ground connections that aggressively dig into metal. Maybe they’re onto something. The body shop wanted to do a good job protecting the metal. They did. Good on them. It led to an excellent PHAD case study.
Bad ground behind passenger side headlight. Car was probably involved in a collision,when that fender where all the grounds meet is painted with a: waterborne paint,sticker that protects that area because it is a main ground location is not removed,or just a lot of corrosion!
Love the videos.
Gives new meaning to "turning the lights on"
I keep wondering about ground G09 since that seems to ground several modules. Also since it has new battery and alternator was the problem there before or did it show up after that. I wonder if disconnecting battery cables and hooking them together to clear memories would reset all the modules.
Could you do bidirectional control test like turn on the lights with the scan tool to see if it does same thing could you re flash the FBCM sometimes software goes hey wire also maybe green crusty on that FBCM too on connector
I remember fuse box trouble trees at Honda checking resistance and powers and grounds.
Not watching part one until part two comes out. It will b a good one. All the PHADS r.
I know you scoped the ground wire at the fbcm, but could you back probe that ground at the connector and jumper right to battery ground? Then try the headlights again? If the condition stays the same then you could rule out a faulty ground?
Very interesting one, again. I am not sure this is a ground problem, as one of your tests seem to also indicate, for that particular ground anyway. What I have noticed, or it's an optical illusion, is that although CAN Low (Red trace) does appear to be going from 2.5 Volts down to 1.5 Volts, CAN High (Blue trace) looks to be going from 2.5 Volts to 4 Volts, or so. This is before you turn on the flashers or headlights, start the car, or anything. CAN High looks to be incorrect, or I just cannot tell for sure from my POV, if it is correct.
Regardless if the above statement is true or not, it (CAN High, if true) and when something is turned on and the CAN High (doesn't seem to affect CAN Low much) goes really high (7 Volts or so) it appears to me that some module is causing CAN High to go higher than it should. Maybe the ABS, or some other module more directly related to the lights, etc., than the ABS?
My next step would likely be, given what I know from the video, to disconnect the ABS module (or other module, if there is one, involved with these loads) and see what happens, then go from there. I think disconnecting modules one at a time, and also first checking that the resistors across the CAN High and CAN Low (two 120 Ohms in parallel, providing 60 Ohms) are correct might be good next steps. Modules on the High Speed CAN bus or connect to it through some other bus, that you can get to rather easily..
Although ground could still play a role here, it appears to me to possibly be a module that is acting up. If true, it could be a bad module or bad power or ground (or some other signal) on that module, wrong termination resistors on the CAN Bus, etc.
A bad (floating) ground (probably on some module in this case) can certainly make a signal go high, so it is still a significant possibility. A final note here is that IF there is a floating ground on a module the higher the current draw (or in this case the more active the CAN Bus is, such as when turning something on), the higher above ground (above 0 Volts) the floating ground will go, up to the maximum of battery voltage. Since the CAN High is powered (driven high, 3.5 Volts when correct) by a DC-DC Regulator powered likely by battery voltage and could have it's ground connected to the above mentioned floating ground, that could cause CAN High (Blue trace) to go high, like we are seeing. CAN Low (Red trace) is driven by a different driver, powered and grounded differently. Just speculation here.
Waiting for part II.
The fact that you're laughing through such an immense challenge is both maddening and inspiring! lol Quite the challenge. Way to go Ivan!
I love our cx5. FORScan works awesome on them.
Turn on other high draw items like rear defrost and fan, do you get same result? What does power to module look like? Is there A/C ripple when load is increased?
I was thinking the same, but then he did get the network to go crazy with engine off.
Same here had a instance where a short in multifunction switch which was also a junction for CAN high it was putting power direct into CAN high and disrupting com with pcm, Ben, and abs because the brake lights also went through MF switch it would make airbag light come on and steering angle sensor screwed calibration each time it happened like you I stumbled on it by accidentally flicking high beam on and everything went dead too much CAN crap in steering column especially if car is fitted with steering position memory for driver memory each time it moves it chafes the looms I don’t care how well they are secured it always happens, pulled the switch apart and found nitrate( sodder residue corrosion) shorting to the can high
Ivan, I would check the grounds near headlight assemblies, all the erratic data is happening with headlight activity, the car may have been in an accident prior.
Throwing my guess out, seeing a new battery and alternator, did someone try jump starting it backwards? Could they have touched the + to something they shouldn't have? I think that's what let the magic smoke out of the FBCM
The KISS Principal says that you start with the simple things first. While Ivan may ultimately find some strange exotic issue that he'll tell us about in part 2, what should have been done first was check the engine to chassis and battery ground to chassis connections first for broken or corroded terminals and wiring/bonding strap, especially vehicles that are operated in highly corrosive environments (like areas where the roads get salted).
I believe I'd redirect my efforts to the ABS module, since it's consistently setting the battery voltage code. I want to know why. The vehicle speed sensor is probably connected to the ABS module, then it transmits that information to other modules over the data lines, which explains multiple codes regarding vehicle speed. All of the questionable modules are located at the front of the vehicle, so it's very likely that they share ground connections. All the problems seem related, so I'm trying to find a common link.
That dash cluster got tazed!
Have the power and ground voltages been checked at the fbcm itself? Maybe I missed that. I'd disconnect the headlights ne at a time in case one has a poor connection on a pin or if power/ground may be fuzzy with corrosion.
Check alternator. Sometime internal voltage regulator can put out to high of voltage can cause limp mode and other odd behavior
Is the 'break-out box' (at 16:52) available alone or is it a part of the Think Tool pkg?
My next step : power and ground at the abs unit connector. The fault code is already there. Love the video's by the way 👌
Just to eliminate one more possibility. Whenever I see a random electrical issue I check alternator ripple. Seems to act up with either a large electrical load or high engine rpm when the alternator output is greatest. It's new, that doesn't mean it's good. It doesn't happen often but only takes a minute to check.
As you point out measurement is key. Digital communication flaws can often confuse analysis because we (humans) take them for granted. I once flew 500 miles to show a customer that one wire of his RS485 differential signal cable was not connected; this digital signal worked "most" of the time even with such an blatant circuit flaw. I've also seen digital gates perform correct logic with no ground signal connection to the IC package; the circuit found it's own return path and operated (almost always) without fault.
Feels like when you activate that module. It is finding a different ground when activating the headlights. Was there LED's installed without a resistors?
Curious to know when the altenator was replaced, prior to issues or as a measure correct the electrical problems.
Perhaps reconnect the FBCM and start unplugging individual modules? In similar fashion to checking a 5V reference short?
It looked like all the lights on on the cluster with the front module unplugged were the same as when you hit the lights. So for me, with the front module ground being good, i’d just be checking it’s power supply under the headlight loaded condition as the next step. In that case, network bias going high could be the front module going open perhaps!?? Maybe from lack of good voltage, or maybe from just being junk!? Lol! If the front module is a gateway, it may be causing unusual havoc with the network if it were to be flashing off-line.
Pull the high beam relay. Shunt the pins to turn on the high beam. Does the high current alone cause the problem? With the relay out, pull the stalk. Put an equivalent resistance across low Amp side of relay and pull stalk. Do power windows, fan on high, door locks, or any other high current draw cause same problem? I suspect the fuel pump is causing the little pulse spikes when you drive. Check negative battery cable connection to chassis.
I say always go back to basics bad ground or a defective headlight switch had this same problem on a non computer controlled truck many years ago where when I turned the headlight switch on the motor stubled and stalled .
I would jump com lines so you get all the other modules online. Dont make the mistake like I have done a couple times and change the suspected module without making sure downstream modules are ok
Do a full load test with all the lights on and check that all the external lights are working and that none have been replaced with crap aftermarket led bulbs or incorrect bulbs. Jump the can wires and bypass the fbcm, maybe only giving the fbcm power ground and can connections to determine if there is an input problem?
Wow seem some weird stuff before, last time seen a dash light up like that all the door switches and relays under dash we’re going off as well. This occurred when trying to start the car. Ended up being there was no metal left in positive batt cable to battery. Cut it in half white power poured out of it like a lot of it! Terminal wouldn’t come of batt hit wrench with a hammer and a saucer sized chunk of batt with terminal came off! New batt new cables and ran like a charm. Turns out no one had replaced batt for 15 years or so…
Ivan if you have to used other scope .what will be your second choice?
why was the alternator replaced?, is the new one any good?
Do the taillights operate from the Rear Vehicle Module? Taillights would come on with headlights and the fault did occur once when you pressed the brake pedal which would also turn on taillights
My first thought was low battery voltage in BCM. I'll keep watching.
Not totally correct, but this blind squirrel was getting close to finding a nut!
Great part 2!
I wonder what would happen if you checked the voltage between pins 4 and5 of the breakout box when. You turn on the headlights.
The next step is basically already stippled out in the bonus footage - bypass the CAN-bus with the BCM unplugged. But I would additionally 'bypass' the high beam output, making the high bean light up even though the BCM is unplugged.
What happened to checking the ABS low voltage? You tracked off to the lights.
Could you remove the module and jumper the pass through can wires ? To confirm that it’s the front module ?
My initial non-scope fix to something like this would be to go around and start sistering grounds with a back probe and a wire to the battery neg terminal. Then, when found, I'd start trying to chase the actual corroded/broken wire (or if the customer doesn't want to pay for that time by the hour, make the sister permanent).
Jumper the network wires that the front module passes through so other modules can come on line. - Then check pwr, gnd and 5v ref on that front module. It loos like any load is pulling something down.
That has to be one of the strangest symptoms I've seen. Why is it just a few systems on the high-speed network? Why not the others? It's acting like you're trying to squeeze 300 amps worth of service down a 24-gauge wire... So strange. It seems like it's a power distribution issue for sure. Like a loose or poor connection or a bad relay. I would most likely start with powers and grounds at the ABS module and work my way out. I'm guessing that the problem is in the main fuse box somewhere. Good luck Ivan. I'm looking forward to part 2.
Since FBCM is pass-thru, perhaps you could bridge data lines at the harness of FBCM after isolating it to observe what change if any occurs on data lines. Seems like you're near the culprit. Looking forward to the next episode of this mystery.
what about the parasitic key off current drain test?? 😁 Or was the bus activity with key-off just before going to sleep?
My first idea was bad or loose wiring in multifunction switch, but I think u proved in went farther than that
If that BCM module is just a passive passthrough, how about taking it out, as you had it, and hotwiring so the network is passed through? Quite a weird problem. Thanks, Ivan.
would it be possible to depin the network wires to the FBCM and then bypass the FBCM and bridge the network together and then replug the FBCM back in and test it then? or would that mess up the communication still for the other modules?
I would try disconnecting components that are inputs to the FBCM to see if it’s a specific component that’s causing the issue or the actual FBCM itself. My 2 cent’s! Thanks!
Gotta love electronics. Where’s part 2? Sorry my impatience is overwhelming.
I would go arfter the voltage to the abs module or ground to the headlights or the front control unit
I would check for loose bolt/nut at G03. Seems like voltage spikes when the car jolts over bumps, like loose ground eyelet
isolate/unsolder/scratch thru trace the data line(s) only where it goes into chip to allow the rest to have comm
I think I would first contact the customer to get some history. When did the problem start and what was done when? If it started after a repair that would give us more direction.
Another problematic issue requiring one of the best diagnostic technicians to investigate. Just as well the shop called you Ivan.
First thought at 1:35 min. bad ground and highbeam switch pulls voltage at PCM below 9 volts. Wild guess ?
ABS is complaining about battery voltage.
Right turn signal flashes fast when headlights are on.
I didn't see you do a walk-around and observe what the lights were actually doing outside.
CAN signal voltage bias lifted in response to headlight and hazards
Do the RH headlight and ABS module share a ground?
There is a common ground problem. When head light is on right signal flashes fast and find which bulb is out and see where that grouns from and run external ground the test it.
I wonder if this is the same as that Hyundai he did a couple weeks ago, where the part they changed had a mid production change (eg pre 6/16 pin 1 is power post 6/16 pin 1 is sink signal)
Perhaps the simplest direction is to focus on the misbehavior of the right turn signal. That is where, since I don't have an o'scope, I would go with the data available.
[EDIT: *for the win* the Eric O approach of nail down the easiest thing first]
Scotty always says check the condition of the battery when electrical problems happen. I would check the condition of the battery and charging system first but I'm sure you already have done this right?
My next test would be to remove power to fbcm with it connected, in theory it will pass through the network but an internal short to power would be eliminated.
I would have checked ABS data stream then ABS powers and grounds, given that you had so many ABS DTC's. Why didn't you? You went straight to the network, which showed voltage going high at times, which would indicate a bad ground path. The headlights was a great find. Why didn't you check out those grounds and what else might be on them? Not even a visual inspection? Not curious there, cause I sure am. 🙂
I share your point of few, additionally wrong bulbs may be play a role. Ivan mentioned it is(should be) conventional, non LED.
My first thought is a short on the main bus (network) since so many disparate things are creating codes.
I had a similar problem on a BMW that I eventually traced down to a bad ground on the CAN bus for the (drum roll) the Sirius Radio module. When the issue would happen it would strand me, and it would happen randomly. Not fun in city traffic.
What would I do next? Ideally, you'd like a 2nd module that you disconnected to see if that's causing the problem. Failing that, I'd bypass the control module jury-rigging some clips to let the other control modules come online and see what happens.
As a third choice, I'd put the original module in and disconnect the downstream modules one by one to see which is causing the problem.
@@teekay_1 A short generally brings voltage down though. The network voltage raises in this case, suggesting to me a bad ground causing current flow in odd places.
@@andybonneau9209 Maybe, but a short also causes voltage surges, which can affect low voltage components in interesting ways.
When I diagnose electronics equipment, I try to isolate components in a logical way, to essentially mark off components to a known good state. It's more difficult in a car primarily because it's hard to get to the wiring and modules so you can do it quickly.
I think that's what frustrates most people when doing electronic debugging in a car, it's just a pain in the rear end to physically get to some of the components.
I would disconnect the lines that activate lights and see if the issue still happens. If it no longer happens, it would mean something's wrong in the light circuits (unlikely, but still). If it still happens, it would most likely mean the module is bad.
Current induced by unshielded wire when lights turned on ?
Battery voltage issue someplace. Go back to ABS, probably bad ground or Alternator/regulator issue.
POPCORN HELL. Need a few bourbons after this one.