A friend has a '99 Coupe that he took to his friendly dealer and they say he needs a new BCM. New it is $1800 and they said they could get a remanufactured one for $600. They've had the car for 4 weeks and still haven't located a remanufactured part. Does anybody repair these things? Any suggestions on finding an affordable part? What problems if you drive the car as is? When he took it in the rear hatch wouldn't open and his battery was down once but started with a jump and drove fine. Help please!

 

There have been a few bad BCM's but not many. Usually water dripping onto or into the BCM from plugged up udders is the usual cause. This one having been jumped and started means its not too bad if at all. Pull the codes and post them.

 

$1800 for a BCM!: lol: That MUST be the GOLD plated one that does sexual favors!

Contact Gene Culley www.gmpartshouse.com and see what their price is. The swap is a THREE PLUG Disconnect and reconnect. You will need to SYNC it to the PCM and maybe have the RPO Codes reflashed by a dealer.

What are the symptoms that your having and what are the DTCS that are displayed in the DIC???

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.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

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

Here are some very good sites that explain what DTC mean:

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!!

 

Thanks once again for your time and help. I think my friend is going to get his car back from the dealer on Tuesday and seek help elsewhere. I think reading the codes would be a good start. I did find out that he has had a problem with a wet passenger carpet so I assume his AC drain is blocked and that might have helped start his problem.

When I had an ABS problem this spring the guys on the Forum told me about the ABS Fixer and by doing this myself I checked prices with a local dealer and figured out I saved $1454 by doing this myself on this one simple repair!

 

If the BCM got water inside of it, then you can disconnect the battery first, then pull the bcm out. Using a grounding wrist-strap, open it up and use iso alcohol with a q-tip and clean out the contamination. Put it back together and reconnect everything. You might get lucky. Now the problem of the blocked udders would need to be resolved immediately otherwise it'll just happen again.