bcm or what?
#1
11-29-2007 | 08:20 AM
Thread Starter
|
Newbie
Joined: Nov 2007
Posts: 5
bcm or what?
edited forgot to mention that i have an 96 4th gen camaro if thats helps any
wondering if anyone has+/- any ideas of what can be the problem my car has been sitting for about 6months cause of bad motor/engine when i finally do replace the engine 6months later my car will not crank,start,fire or anything my mechanic replace everything we thought would have been the issue like the lock cylinder(the wires was shortened) brought brand new sets of keys correct chip size and measurement all from dealership brought brand new car battery....now when i put the key into the ignition turn to POWER ON i dont hear no click or ticking sound whatsoever,car is stuck in park gear as well my factured alarm lights(anti-theft security light)on dash will blink really fast....the dealership says sounds and looks like my bcm is screwed and i will need an newone but aftergetting under my car and poking the starter with an screwdriver it will run for 3seconds and shut right back off doesnt really sound like $800 of work???
wondering if anyone has+/- any ideas of what can be the problem my car has been sitting for about 6months cause of bad motor/engine when i finally do replace the engine 6months later my car will not crank,start,fire or anything my mechanic replace everything we thought would have been the issue like the lock cylinder(the wires was shortened) brought brand new sets of keys correct chip size and measurement all from dealership brought brand new car battery....now when i put the key into the ignition turn to POWER ON i dont hear no click or ticking sound whatsoever,car is stuck in park gear as well my factured alarm lights(anti-theft security light)on dash will blink really fast....the dealership says sounds and looks like my bcm is screwed and i will need an newone but aftergetting under my car and poking the starter with an screwdriver it will run for 3seconds and shut right back off doesnt really sound like $800 of work???
#2
11-29-2007 | 02:55 PM
Tech Droid
Joined: Aug 2005
Posts: 9,215
From: North East PA
RE: bcm or what?
The BCM sits under the dashboard and it is a PIA to replace. The BCM tells the PCM that the proper key is in the ignition, the PCM in turn allows the FI to deliver fuel, and energizes the start relay so that power goes to the starter solenoid, which in turn engages the starter.
BCM Replacement
IMPORTANT: If the BCM is replaced, refer to BCM Programming/RPO Configuration to program the new BCM to the current ignition key. Remember the BCM can only be programmed once.
Do not replace the BCM unless directed to do so by the diagnostic procedures in this section. Most system faults are traceable to faulty wiring, connectors or system components other than the control module. Do not replace the BCM before performing a complete diagnosis. This may result in the replacement of a good BCM and a recurrence of the fault.
Body Control Module (BCM) Programming/RPO Configuration
IMPORTANT:[*]Any new BCM will automatically program to the resistance of the ignition key being used at the first ignition ON cycle. This can only be done once for the life of the module.[*]The BCM can only be programmed to one ignition key resistance. All ignition key resistances must match.
[ul][/ul]A new BCM is not programmed. Before the system will function properly it must be programmed to the code that matches the customer's keys.[*]Insert one of the customer's keys into the ignition cylinder and turn it to the ON position. Stan the engine at this time in order to verify system operation.[*]Observe the SECURITY indicator lamp for the following conditions:
[ol][/ol]
[ul][*]GOOD--The indicator lamp lights steadily for approximately 5 seconds and then goes out. This indicates that the BCM is programmed properly.[*]BAD--The indicator lamp flashes at a rate of one flash per second until the ignition is turned OFF. This indicates that the BCM did not program and the system should be checked for a fault. Refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent.[/ul]
[ul][/ul]Body Control Module Replacement
REMOVAL PROCEDURE[*]Disconnect the negative battery cable.[*]Remove the instrument panel (IP) insulator.[*]Release the body control module (BCM) (3) from the HVAC duct (1).[*]Disconnect the electrical connectors (2) from the BCM (3).[*]Disconnect the IP harness extension from the BCM.
[ol][/ol]
INSTALLATION PROCEDURE[*]Connect the IP harness extension to the BCM.[*]Connect the harness electrical connectors (2) to the BCM.[*]Align the BCM to the duct.[*]Install the BCM (3) to the HVAC duct (1). Press into place until the BCM is fully seated.[*]Install the I/P insulator.[*]Connect the negative battery cable.[*]Perform the programming procedure. Refer to BCM Programming/RPO Configuration.
[ol][/ol]
BCM Replacement
IMPORTANT: If the BCM is replaced, refer to BCM Programming/RPO Configuration to program the new BCM to the current ignition key. Remember the BCM can only be programmed once.
Do not replace the BCM unless directed to do so by the diagnostic procedures in this section. Most system faults are traceable to faulty wiring, connectors or system components other than the control module. Do not replace the BCM before performing a complete diagnosis. This may result in the replacement of a good BCM and a recurrence of the fault.
Body Control Module (BCM) Programming/RPO Configuration
IMPORTANT:[*]Any new BCM will automatically program to the resistance of the ignition key being used at the first ignition ON cycle. This can only be done once for the life of the module.[*]The BCM can only be programmed to one ignition key resistance. All ignition key resistances must match.
[ul][/ul]A new BCM is not programmed. Before the system will function properly it must be programmed to the code that matches the customer's keys.[*]Insert one of the customer's keys into the ignition cylinder and turn it to the ON position. Stan the engine at this time in order to verify system operation.[*]Observe the SECURITY indicator lamp for the following conditions:
[ol][/ol]
[ul][*]GOOD--The indicator lamp lights steadily for approximately 5 seconds and then goes out. This indicates that the BCM is programmed properly.[*]BAD--The indicator lamp flashes at a rate of one flash per second until the ignition is turned OFF. This indicates that the BCM did not program and the system should be checked for a fault. Refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent.[/ul]
[ul][/ul]Body Control Module Replacement
REMOVAL PROCEDURE[*]Disconnect the negative battery cable.[*]Remove the instrument panel (IP) insulator.[*]Release the body control module (BCM) (3) from the HVAC duct (1).[*]Disconnect the electrical connectors (2) from the BCM (3).[*]Disconnect the IP harness extension from the BCM.
[ol][/ol]
INSTALLATION PROCEDURE[*]Connect the IP harness extension to the BCM.[*]Connect the harness electrical connectors (2) to the BCM.[*]Align the BCM to the duct.[*]Install the BCM (3) to the HVAC duct (1). Press into place until the BCM is fully seated.[*]Install the I/P insulator.[*]Connect the negative battery cable.[*]Perform the programming procedure. Refer to BCM Programming/RPO Configuration.
[ol][/ol]
#3
12-13-2007 | 08:00 PM
Newbie
Joined: Jun 2006
Posts: 29
From:
RE: bcm or what?
Hello Pete,
I have problems with my BCM too, the car works perfectly but:
- The remote keyfob does not operate the central lock (I can open and lock the door only with the manual sliding lock or the door key).
-The courtesy lights which were working OK, now don't work and the fuse blows (replaced it twice already). The bulbs are the correct type and the fuse amp rating is correct too.
-the new door lock buttons do not operate the solenoids (they worked fine for a few days before the BCM started acting up).
-it causes a clicking noise every 10 seconds under the glovebox which I'm afraid is draining my battery.
The keyfob still arms and disarms the alarm and flashes the turn signals and honks the horn when doing so. the 3rd. button still unlocks the hatch. My car has not been tampered with, has no aftermarket electronics, even the radio is the original delco-Bose one.
No auto parts store (napa, autozone, pep boys, advance, etc) carries a BCM for my Camaro, there are used ones on EBay, but I can only get it new from gmpartsdirect.com and it costs $138 + shipping...
After reading everything in websites and forums including conflicting information and dissassembling some pieces in my car, I found my OEM BCM part is 16243951 (stamped "made in Singapore" damn!).
- As you say I can't buy a used BCM, because the BCM chip programs itself with the Pass-key code the first time the ignition is turned to run. I would have to get one with the same ID as mine, which I don't know which one is so anyway I have to shell out the $138 + shipping. So I resigned myself to having to buy it new before my actual one gets worse and disables the ignition or something.
-I called a big place that refurbishes ECU computers here in FL, but they don't mess around with BCMs. they said: "There is programming involved in the car so we don't do it, its complicated go to a Chevy dealership"
-would the BCM act up because of a low battery? my starter is not in very good condition (I'm changing it tomorrow) so when hot it seems like it drains every last watt of current, even the dash lights dim while cranking, and it cranks slowly too. Could this cause the BCM to be damaged someway? is there someone who repairs this, or any way to check it and replace an internal relay or something?
You mention "disconnect the IP (instrument panel) insulator. Which piece is that? the cover over the passenger side footwell? does the BCM configure itself then? no need to program anything else? I am scared of spending $138 for the part, replacing it and then something goes wrong and the car won't work at all.
Thanks for your help!
I have problems with my BCM too, the car works perfectly but:
- The remote keyfob does not operate the central lock (I can open and lock the door only with the manual sliding lock or the door key).
-The courtesy lights which were working OK, now don't work and the fuse blows (replaced it twice already). The bulbs are the correct type and the fuse amp rating is correct too.
-the new door lock buttons do not operate the solenoids (they worked fine for a few days before the BCM started acting up).
-it causes a clicking noise every 10 seconds under the glovebox which I'm afraid is draining my battery.
The keyfob still arms and disarms the alarm and flashes the turn signals and honks the horn when doing so. the 3rd. button still unlocks the hatch. My car has not been tampered with, has no aftermarket electronics, even the radio is the original delco-Bose one.
No auto parts store (napa, autozone, pep boys, advance, etc) carries a BCM for my Camaro, there are used ones on EBay, but I can only get it new from gmpartsdirect.com and it costs $138 + shipping...
After reading everything in websites and forums including conflicting information and dissassembling some pieces in my car, I found my OEM BCM part is 16243951 (stamped "made in Singapore" damn!).
- As you say I can't buy a used BCM, because the BCM chip programs itself with the Pass-key code the first time the ignition is turned to run. I would have to get one with the same ID as mine, which I don't know which one is so anyway I have to shell out the $138 + shipping. So I resigned myself to having to buy it new before my actual one gets worse and disables the ignition or something.
-I called a big place that refurbishes ECU computers here in FL, but they don't mess around with BCMs. they said: "There is programming involved in the car so we don't do it, its complicated go to a Chevy dealership"
-would the BCM act up because of a low battery? my starter is not in very good condition (I'm changing it tomorrow) so when hot it seems like it drains every last watt of current, even the dash lights dim while cranking, and it cranks slowly too. Could this cause the BCM to be damaged someway? is there someone who repairs this, or any way to check it and replace an internal relay or something?
You mention "disconnect the IP (instrument panel) insulator. Which piece is that? the cover over the passenger side footwell? does the BCM configure itself then? no need to program anything else? I am scared of spending $138 for the part, replacing it and then something goes wrong and the car won't work at all.
Thanks for your help!
#5
09-16-2010 | 08:41 PM
Newbie
Joined: Sep 2010
Posts: 1
Hey Pete,
i think I'm having some bcm problems as well. I have a 1999 z28 and the alternator went bad on me about a year ago and started giving me overvoltages around 18v. i was 100 miles from home so I continued to drive with the overvoltages and about the time I got home things started acting screwy. mainly the driver window was rolling itself up and down. after changing the alternator, the window would roll itself down when the key was turned but would stop as soon as i pushed the up button. as soon as i let the button go, it would continue going down. I assumed it was the windows auto down relay and just wired around it. that worked, for a while. things have slowly gone down hill. I recently lost functionality of my Speedometer, Tachometer, fuel gauge, and temp gauge as well as the key fob no longer opens the trunk. Is any of this to do with the BCM? I'm wondering if the overvoltage fried some of the circuitry and its just slowly wearing out.
i think I'm having some bcm problems as well. I have a 1999 z28 and the alternator went bad on me about a year ago and started giving me overvoltages around 18v. i was 100 miles from home so I continued to drive with the overvoltages and about the time I got home things started acting screwy. mainly the driver window was rolling itself up and down. after changing the alternator, the window would roll itself down when the key was turned but would stop as soon as i pushed the up button. as soon as i let the button go, it would continue going down. I assumed it was the windows auto down relay and just wired around it. that worked, for a while. things have slowly gone down hill. I recently lost functionality of my Speedometer, Tachometer, fuel gauge, and temp gauge as well as the key fob no longer opens the trunk. Is any of this to do with the BCM? I'm wondering if the overvoltage fried some of the circuitry and its just slowly wearing out.
