OK Forum, I need your help.
My C5 has had a 'stroke', and is now in need recovery. Here's some background

About 2 months ago while driving under normal conditions, the DIC showed "Reduced Engine Power", the fuel gage went to zero, airbag light came on, tire pressure monitor gave an error message, "Service Traction Control" display also showed on the DIC, and window and lock on the passenger side would not function.

I immediately stopped. Turned the car off. Waited about a minute, and turned her back on. Everything went back to normal. I had a similar incident about a year ago when my battery was about to go dead. I concluded (wrongly I think) that I had left something plugged in the cigarette lighter for a while when my car was parked. So drove it a little extra, to hopefully charge the battery some

About a week later I had the same incident.

A few days later, I went to start the car....nothing. I jumped it, and let it idle. Then tried to start it again. Nothing. I was now pretty sure it was the alternator. I jumped it again then tried to drive down the street. Everytime I came off the clutch, the engine would die. Even if I dumped it, it would just stop. My thinking then was that somehow, the car did not have enough "juice" to keep the car idle high enough for me to get in gear.

Fast forward to now. I had the car "flatbeded" to a local garage (my local Chevy dealer sucks, and wanted to charge me double for an alternator). They replaced the alternator, drove it down the street and thought it was good to go. When I try to drive it, I get the same error messages I had two months ago, plus the car would "die" when I tried to put it in gear. I literally had to start the car, and feather the clutch and gas 20 times to get it back to the garage.

When the garage hooked there OBD devive to the car, it reported that the theft deterrent system was engaged. The thought then was that the battery had a bad cell, and was giving insufficient voltage the the ECM and other systems, making them act erratically. Since the battery (Diehard Gold) was still in warranty, I decided to try to make it to Sears. After disconnecting the battery, hoping that the theft system would reset, I made it to Sears. They show the battery is fine. Meanwhile, anytime I try to drive more than 2 miles, I get the dashboard "Christmas tree", along with Reduced Power. Futher, if a shut it off, I get the same "dying in gear" syndrome. And the passenger side lock and window still dont function.

Pulled some DIC codes. All are history (end in H)
TCS 1301, 1287 and 1288
BCM 0432, 0502, 0507, 7981, 2521, 2482, 1255, 1016, 1096
a few other others, but notably, a "no communication" code ( I think this was the RDCM...go figure)

I was able to get the car home, but it won't get far. And it won't get there fast

I'm checking all the ground connections, as this sounds like the prime suspect


Thoughts????
BCM issue?????
Electrical fault????
Loose connections????




Update: Took the battery out and had it checked again (shows good) and fully charged.
Going through ground connections next

 

The RDCM No Comm is the place to start with this mix of messages and codes. Check the wiring and the connectors that run in the accordion between the body and the passenger door.

 

I've seen a problem where water gets into the passenger side because of clogged ac drains. This water gets on the bcm and all kinds of troubles occur..pull the carpet back to see if its damp. also check the battery connections on the starter to see if they are clean and tight..might help

 

My money is on corroded grounding points

 

Try disconnecting and reconnecting the battery; it worked for me.

 

Some stated above, check grounds, check for battery connections which I agree with, but make sure you check the connections at the started solenoid as this is a junction point for power coming from the alternator and will cause similar problems. Check for the water or trace minerals left behind in the passenger footwell as mentioned too. It's most likely one of these issues.

 

"My C5 has had a 'stroke'" I got a kick out of that statement but sadly,,,Ive been there done that. Sounds like you have one of the following issues:

1. BCM is getting damp or wet. Do a very good investigation and check all of the carpet in the passengers foot well and the carpet underlayment for being damp or wet. The water tends to collect in the middle under the passengers seat area if there was a leak. If the BCM gets wet,,it will have a coronary. If it gets wet enough times,,it will DIE! That means $$$$$$$$$$$$$$$$$$$$$$.
My bet is this is the issue.

2. If the serial buss grounds or shorts, it too can cause similar symptoms. The most likely area that this can happen is the in the door accordion tubes. The door wiring harness connectors commonly have a bare wire that causes this. Pop out the rubber tube out, pull up the connectors from the body well and inspect the connectors.

There are TWO small thin grey connectors to the LEFT of the BCM in the foot well. Those are the STARR CONNECTORS and where the serial buss all connect together. Make sure that the top of the connectors (shorting bars) are pressed on the connector correctly.

BC

 

All,
Thanks for all the suggestions. Here's where I am now. Specifically checked the G104/108 (had to visual and tug on it...WHAT SIZE NUT IS THAT?????) and G202

Did a visual on the bottom of the passenger side footwell and it looked dry as a bone. No evidence of water seepage, sediment, etc. All connections seem tight and in place.

Door - took the accordian rubber gasket loose on both sides and tried to pull any excess wiring through to inspect. Could not get it free. The only other option is removing the door panel ( Is that difficult??

I did see some post about the relearn of the RDCM after a dead battery. I'll dig deeper into that one.


BTW - great post Bill. In case you ever wondered, the PED on the connectors stands for Packard Electric Division (of Delphi Automotive). I might make a call or two for some extra connectors and terminals

I had pics....but having trouble uploading

 

You do NOT need to remove the door panel. The door wiring harness slack is inside the DOOR FRAME pocket. Here is a pic:





Reprogram the DCM?????? No such thing There a plug and play module. If they have issues, they will pop a code. All you need to do is clear the DTCs

BC

 

OK...buttoned everything back up

Put the key in the ignition

....she starts.....an automotive symphony in V8 harmony

Put her in reverse to pull out the drive way. Engine cuts out.....symphony abruptly stops

"PULL KEY, WAIT 10 SECONDS"

"STEERING COLUMN LOCK"



Another symphony. This time of 4,5 and 6 letter words the likes of which hadn't been heard in this part of Alabama since......since the last time I had that happen and had the dealer "fix" the issue


I think I'm at least down to 3 problems possibly less
1. pulling the BCM and bypassing the GM fix
2. making certain the BCM is in good working order
3. Getting my F)$*$)ng socket wrench from below the battery 'well' where I dropped it





Update 2.1
I got my #@)@)!g wrench

 

nice post helping the OP out....might I recommend a suggestion to you though....Check out this pic Bill. You have a bare wire exposed my man! Might want to get some electrical tape on that before you start to have problems.

 

Have you done the column lock bypass on your car?? Try cleaning your key with rubbing alcohol and trying it again. Looks like a column lock issue to me which the car won't drive if it thinks someone is stealing it....

 

Jeff

Thats the point to the post. Almost every C5 I check, that wire is bare. Every once in a while, it will short against something and cause the car to have a fit. Most common symptom of a shorted door wire is the doors will stop working but, I was 160 miles from home once and it caused the car to NOT START and the gages to freak out.

Thats when I found this issue and started reporting on it. My wire has been liquid electriacl tapped up for years and hasnt giving me an issue since.

Every C5 owner should check and repair that wire if it is bare.

BC

 

OK....finally getting a chance to get back to work on the car.
-I put the battery back, put the key in the "on" position, pulled fuses 23,25 and 29. Then replaced
-Started her back up....NO WARNINGS (Service Column Lock gone)
-Pulled out of the driveway.... no issues (fuel pump cut-off reset)

we can stand up....let's try to walk

Went around the block

Christmas tree dash
REDUCED ENGINE POWER
CHECK TIRE SENSOR
LOW FUEL (I have a full tank)

Pull in the garage. Turn it off. Turn it back to "on"
PULL KEY, WAIT 10 SEC
put the key back in
SERVICE COLUMN LOCK (but the steering wheel turns)


I'm back to checking for a grounded wire
I'll start with the passenger door

 

Been there. I would replace the BCM it also may need to be reprogrammed too. Mine would get really hot to the touch. Good luck!!