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Hello Gang,
I have 2000 Convert with just over 200K on the clock and I'm slowly bring back to life. I do try to reseach as much as possible before posting, I do a have background in Electronics, and I know how to turn wrenches. As an example, I'm one of those that won't think twice about ripe out the drivetran in the garage over the weekend to fix a rear main bearing seal. If you know you know!
Ok, have this issue where the Instrument cluster gauges go dead or maxed, "Reduced Power" check gauges" Low Fuel", "Power Window loss" and "HVac" or A/C all stop working until I shut the car off, and restart. I'm thinking this could be a bad Body Controller module, thanks to the heater core leak a few months back. Has anyone seen this type of issue, and I'm I correct to assume this module is going bad? I thought this was a ignition switch issue as I had other issues, but I have since installed a push button, and the issue still appears every now and again. Seems to be worse when it rains. I have to check for leaks around this area; its too damn hot in Florida. I have uploaded a photo. Thoughts?
Pay no attention to the ABS and Traction lights. This is a 2000.
Sounds like a serial data bus issue….you can follow this procedure below when you see all the messages pop up…..
your background in “electronics” and electrical are not quite the same when it comes to cars.
1) Locate the 2 Star Connectors to the left of the BCM and remove the buss bar or “comb” from star connector #2…it has 4 wires on it…see if the car starts…if no start go to next step.
2) Now remove the comb off the other star connector leaving both combs removed…make a jumper wire and jumper the BCM to PCM…light green to dark green wire….if car starts you have a module other than the BCM and PCM on star connector #1 pulling the data bus down….if car still doesn’t start the module pulling the bus down is either the BCM or PCM…go to next step.
3) Take your jumper wire and connect from the purple wire (data bus wire) to the PCM (dark green wire)…now with your scan tool see if you can communicate with the PCM…if you can now communicate the PCM is good and issue may be the BCM…to see if the BCM is indeed bad take the jumper wire and connect the jumper now to the BCM (light green)…with a scan tool that can communicate with ALL modules (NOT a code reader) and if you can’t communicate we can “assume” BCM is bad…for single module “no comm” you want to check the powers and grounds to that module.
Sounds like a serial data bus issue….you can follow this procedure below when you see all the messages pop up…..
your background in “electronics” and electrical are not quite the same when it comes to cars.
1) Locate the 2 Star Connectors to the left of the BCM and remove the buss bar or “comb” from star connector #2…it has 4 wires on it…see if the car starts…if no start go to next step.
2) Now remove the comb off the other star connector leaving both combs removed…make a jumper wire and jumper the BCM to PCM…light green to dark green wire….if car starts you have a module other than the BCM and PCM on star connector #1 pulling the data bus down….if car still doesn’t start the module pulling the bus down is either the BCM or PCM…go to next step.
3) Take your jumper wire and connect from the purple wire (data bus wire) to the PCM (dark green wire)…now with your scan tool see if you can communicate with the PCM…if you can now communicate the PCM is good and issue may be the BCM…to see if the BCM is indeed bad take the jumper wire and connect the jumper now to the BCM (light green)…with a scan tool that can communicate with ALL modules (NOT a code reader) and if you can’t communicate we can “assume” BCM is bad…for single module “no comm” you want to check the powers and grounds to that module.
Thank you for this information, I was able to reproduce the issue once the star connector was disconnected. However, following step 3 did not really help with my Autel scan tool, I was able to communicate with most of the modules, with the exception of the ECBM, that's been dead for some time. I'm not finished yet with the drivers door diag, and I'm thinking of pulling the wiring and run some continutinty testing. The difficult part is this issue is intermittent, and usually during for first few minutes of start up. Leaning towards a bad ground or frayed wire somewhere perhaps. I have already gone through most of the grounds and cleaned with a wire brush until bare metal, ( G111 by Battery today) and the o-ring connectors, followed by some marine grade anti-corrison spray on top. So far, none of these really helped, but I at least I have prevented a future issue. Tracking down under the dash star connectors and grounds is quite the challange due the limited space, and the Florida heat. I'm dripping from only an hour worth of work!
I would still like to track down ( G105, 901) just for good measure, and the areas around the BCM are dry.. It did rain while I was at the gym last night.
Looking at a wire hardness on Ebay as a visual reference, does not look too bad if I had to remove the wiring for testing and repairing. Any additional suggestions are welcomed and appericated!
What module or modules can you communicate with ??…if the data bus is shorted to power or ground your scan tool will not be able to communicate with any module and the car will not start or start and stall…what part of Florida you located ??
What module or modules can you communicate with ??…if the data bus is shorted to power or ground your scan tool will not be able to communicate with any module and the car will not start or start and stall…what part of Florida you located ??
I was able to communicate with all the Modules except for the EBCM, as I mention earlier. I pulled the wiring harness for the driver and conducted a continuty test, and did not find any issues. However, I did notice after reasembling the connector on the inside under the dash, I noticed the cabin light flicker. Sure enough, on the 6 pin connector, one of the pins was not making a good connection. I clean the pins with Electric terminal cleaner, and bent the pins from the rear to ensure a good connection, and retape the entire hardness with electrical tape, and the orange tape was falling apart. We'll see in time if this was the issue.
BTW, I'm on the East of Florida in Martin county, just above Jupiter.
Again, I appreciate your help in helping to diag these electrical issues. Sometimes, you just have to slow down and do a visual before going crazy with diagrams and such.
If you still have issues see Brin Kline over at Assured Auto in Melbourne… a very SHARP diagnostic Tech…if no comm with EBCM check its powers and grounds and remove the comb on that splice pack and clean it with emery cloth…if that one comb “tooth” is oxidized you will not have communication either.
Gauges go dead until restart
