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Impalaforums.com
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Discussion Starter #1 (Edited)
Body Control Module Replacement

Removal Procedure




  1. Important
    You must perform the new body control module (BCM) setup when replacing the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration .
  2. Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Remove the left instrument panel insulator. Refer to Closeout/Insulator Panel Replacement - Left in Instrument Panel, Gages and Console.
  4. Disconnect the BCM electrical connectors (2,3,4).
  5. Remove the BCM (1).
Installation Procedure



  1. Install the body control module (BCM) (1).
  2. Connect the BCM electrical connectors (2,3,4).
  3. Install the left instrument panel insulator. Refer to Closeout/Insulator Panel Replacement - Left in Instrument Panel, Gages and Console.
  4. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  5. Perform the new BCM setup. Refer to Body Control Module (BCM) Programming/RPO Configuration .
Body Control Module (BCM) Programming/RPO Configuration

Introduction


During body control module (BCM) related service, the procedures below are designated to set-up the BCM correctly. Before you start, read these procedures carefully and completely.
Setup New Body Control Module (BCM)








Important
The BCM will not function properly if the Setup New BCM procedure is not performed.





Make sure the battery is fully charged before performing the setup procedure.
Make sure all disconnected devices and connectors have been reconnected
Perform the Theft Deterrent Re-learn procedure after successfully finishing the Setup New BCM procedure. Refer to Programming Theft Deterrent System Components in Theft Deterrent. If the Theft Deterrent Re-learn procedure is not performed after a BCM replacement, the following conditions may occur:
- The vehicle will not be protected against theft by the PASSLOCK system.
- The engine will not crank nor start.

  1. Connect a Scan Tool (Tech 2) to the Data Link Connector (DLC).
  2. Turn the ignition switch on.
  3. Select Diagnostics and input all of the required data when prompted by the Scan Tool (Tech 2).
  4. Select BODY CONTROL MODULE.
  5. Select SPECIAL FUNCTIONS.
  6. Select Setup New BCM.
  7. Note, Input all of the required data when prompted by the scan tool.
  8. Select Setup SDM Part Number in BCM, and follow the onscreen directions.
  9. Select New VIN, and follow the onscreen directions.
  10. Select Option Configuration, and follow the onscreen directions. .
  11. Select Point of Sale, and follow the onscreen directions. .
  12. Exit back to the SPECIAL FUNCTIONS menu.
  13. When the BCM, VIN, Point of Sale and Option Configuration have been entered, proceed with the Theft Deterrent Re-learn procedure.
  14. If the scan tool displays UNABLE TO PROGRAM BCM. BCM IS SECURED, then the BCM must be replaced and this procedure must be repeated on a new BCM.
NOTE: After the above procedure has been completed, personalization of the BCM defaults to a default setting. Inform the customer that the personalization settings must be set again.

Important


After programming, perform the following to avoid future misdiagnosis:

  1. Turn the ignition OFF for 10 seconds.
  2. Connect the scan tool to the data link connector.
  3. Turn the ignition ON with the engine OFF.
  4. Use the scan tool in order to retrieve history DTCs from all modules.
  5. Clear all history DTCs.
 

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8th Gen Antagonist
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You can replace it 10 times at the dealer before the cost of the tech 2 will be made up though.
 

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8th Gen Antagonist
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Well, when you consider a tech 2 is about $2500, and less than $300 of the cost of the BCM replacement is labor... At any rate, they usually don't go bad more than once. Its nice to see the procedure laid out, I just don't think anyone will be able to use it.
 

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Impalaforums.com
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Discussion Starter #6
I seen the tech 2 going for 1500 to 2000 brand new.
I wish I new someone close that had one I could borrow!
I hate taking my car to the dealership or any shop to get it fixed. I like to do it myself but some things just need to be that way I guess.
I posted this in the 7th gen discussion instead of the DIY section just because of the point you bring up.
 

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8th Gen Antagonist
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Last time I looked at them, they had them for that price, but they were missing either the cable, or the software to make them work, and it was an extra $500 for that part. I would kill for one of those things, especially here at work... Anyway, this can still be useful to someone who does have one, or has access to one.
 

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Storm Trooper Ralf
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while i was going to school we had a ton of tech 2's and snap on diag tools like the motis laying around brand new and un-inventoried, i should got one lol
 

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Super Moderator
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This may be whats wrong with my car. Looks like I am going to have to live with it fo a while.
 

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8th Gen Antagonist
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Unless there is some special cable adaptor that I'm unaware of, either way you DO need a tech 2.
 

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8th Gen Antagonist
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You could always ask the dealer, I'm not sure.
 

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8th Gen Antagonist
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I would just replace it in their parking lot, it only takes like 5 minutes and no tools.
 

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I would just replace it in their parking lot, it only takes like 5 minutes and no tools.
Really? That's it? Hmmmm... I'll have to test myself.

I do do all of my own maintenance (struts, brakes, you know), but I've never even seen the BCM. All I know is that it's under the air cleaner... Is there a step by step anywhere on the forums for this? Haynes is kinda vague.

Lol, I said "do do."
 

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8th Gen Antagonist
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No, the PCM is under the aircleaner, the BCM is under the dash on the drivers side. Look at the first post in this thread, don't worry about disconnecting the battery cable.
 

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I know this is an old thread, but I managed to fix mine by removing the bcm from its holder and resoldering all the joints for the connectors. There were at least 2 cold solder joints. The problem would only happen on sunny days when the car would get hot inside. Try unplugging the unit and plugging it back in 1st. That would let ours start up and run normally. Of course try at your own risk, but if the controller is bad and you can solder printed circuit boards properly, you really have nothing to lose.
 

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Bumping this old thread for a couple things. 1. They're selling preprogrammed BCMs online so installing the BCM before programming might be necessary. You give them your VIN and they program it for you ahead of time. 2. Looks like they're selling cheap Tech 2s now for under $400.
 

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Figured it was worth a shot as suggested by shamoo. I cleaned and re-soldered all the connector pins on the BCM PCB. No change to faults I'm having with my 2002..

DIC dead.
Cruse control stopped working.
HVAC has a mind of its own - recirc, A/C buttons do nothing but it'll randomly switch from recirc to fresh and run the AC so I pulled the fuse that allows the A/C pump to run because it would engage the pump when the HVAC fan was off.

^ These three things all stopped working properly at the same time one day about two years ago.

More recently, occasionally displays low fuel, low brake fluid or door ajar when none of those conditions are true.

Displays service vehicle soon in-between cycling between security and the battery symbol, this was the most recent thing to start happening a - I bypassed the problematic passlock about 6 years ago with a fixed value resistor and never had a problem with it or a warning message displayed until about 4 months ago.

I've pulled every fuse and checked it, none are bad.

Swapping the Overkill PCM out for the original PCM that I kept, no difference except I forgot how rough the factory tune idle is, yuk!

Scanned for codes at different times, none stored.

At the very least the car starts and runs fine still.

I got a recall notice about the dodgy spark plug retainers, I'm thinking I'll get it in to the local Chevy dealer for that and ask them to diagnose the BCM and replace it if its bad.

I keep seeing people mention you can get pre-programmed BCMs with your VIN, but I cant find anyone that offers this.
 
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