Has anyone had to have the BCM replaced in their C5?

Our 99 coupe died yesterday and had it towed to the GM garage this morning. They told me the BCM was going bad.

What happened yesterday was I put the key in the ignition, it started but a bunch of random messages came up (reduced engine power, low fuel, etc). I turned the car off, tried to turn it back on...nothing. Tried to retrain key fobs, etc. Nothing.


Any comments, thoughts on this???


Thanks

 

when you say various message came up - do you happen to know what they were? Did you pull the DTC codes to see what was in there?

 

You have not provided nearly enough detail of the symptoms that you experienced but i would definitely look through the following BEFORE you let the GM $$$$ hounds take a lot of your money:

http://forums.corvetteforum.com/c5-t...n-long-32.html

Than go to post #640.

If that doesn't pan out get ALL the DTC's from the DIC and post them here. Yea it could be the BCM but probably is not.........

If you don't know how to pull DTC's see brlow for a Bill Curlee explanation that I saved:

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

http://www.corvettedoctor.com/Code_Main.html

http://www.corvettedoctor.com/index.html

Go to “technical data base” and then to “Corvette ECM Computer Codes”. Then select your year car. Read the instructions and then scroll down to the "READ MORE" window to view the code definitions.\

Here are some more very good sites:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs

 

Just had one of these installed....not cheap but went to the dealer so I could ensure if any problems it would be backed up. My question is has anyone experienced seat problems after the module was installed. When I got my car back my teh pwer control for my driver's seat waws disconnected and laying off to the side. Dealer screwed it up and dealeer replaced it once I showed the service rep what had happened. I have not been able to position my seat as I normally drive since. The seat pops went trying to adjust it along with difficulty in getting the back to adjust manually or elecrically....everything moves but will not position as it did prior. The front part of the seat bottom is more elevated and will not adjust door as it did prior to this work. My thinking is the seat track is binding and the seat not properly aligned. I suspect they did not tak the seat out properly (I was told they didn't do anything to the seat)(think the svc guy didn't mean it the way it sounded-meaning probably it was taken out and put back in). I suspect they either raised the back to the seat up and installed teh BCM or they took teh seat out simply by unbolting it without first moving the seat forward then back in loosening the bolts for removal and when they replaced it didn't thinkabout tracks being even and aligned. This is not obvious when you look at the seat.
Bill

 

Pull the codes as mentioned. There are two real possibilities...one being the ignition switch itself is failing. Another is a find by Bill Curlee about a wire in the door accordian tube that will short to the frame and cause lots of issues. Another possibility is the battery voltage being low. You need at least 12.5 static across the battery when everything is turned off...tight cables and so on.

 

There would have been no need to remove the driver's side seat at all. The BCM is located in the footwell on the passenger's side under two covers. It takes about a minute to have it out and a new one installed. When a BCM is replaced, it must be reprogrammed with the ignition system or the car will not start. The relates, in part, to the alarm system. The GM scan tool is required. I don't think an after market tool will do this reprogram. Battery voltage is critical when checking the cars computers since many functions of the computer are based on partial voltage readings and any lower than normal voltages will cause the computer or sensor to appear bad.
The sugestion to get the manuals is very important, so that you know before hand whats involved, and can save you big bucks when the $6.00/hr. tech trainee starts looking for problems in the very complicated electrical system on a Corvette. You'll spend about $125.00 for the 3 books.
Reading the codes in the car as described above is simple and the instructions provided here will allow you to post them. There are many here who have been down this very road before. Good luck, we await the codes.