u0100 help with troubleshooting
so yesterday i went found all 3 fuse boxes pulled and checked all pcm tcm bcm fuses and now my tank reads again. but i still have u0100 code
so what i think i am up against is a break in a data wire? when i bought the car i started doing some research on the turbo kit and saw mechanic and individual post expressing burnt wires so i bought a lot of high temp shielding but may have broke a wire while installing the shielding? any suggestions would be greatly appreciated!! thanks so much!! also if there is a scannerdanner type mobile electronic repair guy in the Englewood, Denver metro area i would be willing to hire to help me
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The fuel level data gets to the instrument cluster through the low speed GMLAN from the PCM, so we know that network is at least partly intact and that the PCM is sending the data. There could still be an issue with the high speed LAN, but we'll know more about that from the above questions.
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Got a multimeter? There's a few quick checks you can do to give us a better diagnostic direction. First, turn the ignition on and find a 5V reference sensor under the hood. Something easily accessible. Pretty sure the MAP is right there behind the throttle body? Disconnect it. Connect your multimeter to B- and gently probe all three pins. At least one should have 5V.
You can also check for network integrity and activity at the Data Link Connector. First, leave the key off for two minutes. Find pins 6 and 14 at the DLC.
Switch the multimeter to ohms and gently probe 6 and 14 at the same time. What is the reading? We want to see around 60 ohms.
While at the DLC, turn the ingition on and switch the multimeter to voltage. Connect the meter to B- and check pins 6 and 14 separately for voltage. What are the readings?
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Are you still at the car? If you're positive about the 7.7V reading, then that'd suggest high resistance in a PCM ground circuit. No offense meant here, but since you had the heads off for the head studs, I'd suggest a quick visual on any ground straps before going much further.
I dunno about the Camaro, but I know most other 6.2's had computer grounds at the back of the passenger cylinder head. Plus another heavy ground cable at the front of the block, passenger side.
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The readings you got at the MAP sensor are at least part of the problem. Would you mind going over all three wires again? Meter connected to B-. Let me know what each wire reads.
Depending on what you find there, we may end up heading towards PCM powers and grounds.
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3 Gens wrote: ...and when doing so I was adjusting the wire harness to sit better and I heard a click of a relay then I heard my fuel level low alarm meaning I have no tank reading again. So I might have found the ballpark area of my break. Or one of them.
You're onto something! :woohoo: Perhaps that wiring was heat damaged before you owned it, and manipulating the harness caused some insulation to flake off.
While manipulating the harness, you could rig your multimeter to watch the 5V reference circuit (which was abnormally high last time around). When the readings start changing, you know you're onto something.
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Very glad to hear she's up and running again. You can feel proud of this one - lots of professional techs would have given up or thrown a computer at it. :silly:
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I especially appreciate the CAN network readings you took at the DLC. It helps my diagnostic approach to know how stuff like bad grounds changes readings on the network. I can explain why both lines were at 0V, but not so sure I can explain the zero ohms... Anyone following along is welcome to make suggestions!
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Tyler wrote: Gotcha. The no crank symptom confirms a likely PCM issue. The U0100 code suggests that the high speed LAN is operational, but we don't know that yet.
Got a multimeter? There's a few quick checks you can do to give us a better diagnostic direction. First, turn the ignition on and find a 5V reference sensor under the hood. Something easily accessible. Pretty sure the MAP is right there behind the throttle body? Disconnect it. Connect your multimeter to B- and gently probe all three pins. At least one should have 5V.
You can also check for network integrity and activity at the Data Link Connector. First, leave the key off for two minutes. Find pins 6 and 14 at the DLC.
Switch the multimeter to ohms and gently probe 6 and 14 at the same time. What is the reading? We want to see around 60 ohms.
While at the DLC, turn the ingition on and switch the multimeter to voltage. Connect the meter to B- and check pins 6 and 14 separately for voltage. What are the readings?
I'm sorry for bringing up such an old post but I'm having the same issues and I really could use some help.. I just finished a big project on my 2014 Camaro SS and now its throwing codes U0100 and P0231. I've had my battery tested, I've re grounded all my grounds, checked my fuses, and reconnected my ECM twice and still having issues. The car will start and even sounds good (Appears to run Lean), But i'm getting the codes and a loss of power steering, Also the majority of my readings (RPM etc) aren't pulling up or being read on HP tuners... I check the voltage on my MAP sensor and its reading around 4.7 ish volts, BUT I just checked ohms between pins 6 and 14 and its ranging from -75 to -85 ohms (I'm guessing this is an issue?) Again sorry for bringing up and old post but i've been throwing myself at this for over a week with no avail, I just wanna drive my finished project
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