BCM Issues - Attempting to Program Key Fobs
Thread Starter
On The Tree
Joined: Jun 2012
Posts: 106
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From: Carrollton, Texas
BCM Issues - Attempting to Program Key Fobs Trying to reach shbox or anyone else knowledgeable with BCM issues:
I have been using shbox.com trying to figure out an issue I've been having with my car (96 Trans Am). I determined that there was a problem with my original BCM because the car would no longer crank with the original BCM and the TDR in place. I bypassed the TDR with a paperclip temporarily and was at least able to get the car to run. I ordered an AC Delco reman BCM from RockAuto and just installed it yesterday and put the TDR back in place. Now, the car runs once again without the paperclip bypass, however I cannot get the car into programming mode to get my 2 key fobs programmed into the new BCM. Every time I get to the step of "cycle off-run-off-run-off-run," I hear a clicking noise somewhere on the passenger side (possibly the TDR) rather than the locks cycling like they should to indicate programming mode. I then get stuck having to wait 10 minutes for the Security light to go off before the car will start again. I've unhooked the battery to reset everything and tried once again and got the same results. For some reason, attempting to enter programming mode is tripping the Security light and won't let me proceed with the steps on shbox.com. What should I be testing now to figure out how to fix this so I can program my key fobs to the new BCM?
I have been using shbox.com trying to figure out an issue I've been having with my car (96 Trans Am). I determined that there was a problem with my original BCM because the car would no longer crank with the original BCM and the TDR in place. I bypassed the TDR with a paperclip temporarily and was at least able to get the car to run. I ordered an AC Delco reman BCM from RockAuto and just installed it yesterday and put the TDR back in place. Now, the car runs once again without the paperclip bypass, however I cannot get the car into programming mode to get my 2 key fobs programmed into the new BCM. Every time I get to the step of "cycle off-run-off-run-off-run," I hear a clicking noise somewhere on the passenger side (possibly the TDR) rather than the locks cycling like they should to indicate programming mode. I then get stuck having to wait 10 minutes for the Security light to go off before the car will start again. I've unhooked the battery to reset everything and tried once again and got the same results. For some reason, attempting to enter programming mode is tripping the Security light and won't let me proceed with the steps on shbox.com. What should I be testing now to figure out how to fix this so I can program my key fobs to the new BCM?
TECH Veteran
Joined: Dec 2008
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From: Little Rock, AR
The hatch relay is right next to the TDR, so maybe that is what you are hearing and maybe you are actually in programming mode and don't realize it (can't explain the door locks)? Did you try continuing to the next step? Other than the directions on the site, I don't know too much about the programming. 
Thread Starter
On The Tree
Joined: Jun 2012
Posts: 106
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From: Carrollton, Texas
Yes, I tried continuing on even without the door locks doing anything. Held the buttons on both key fobs (one after another, not at the same time) and then reinstalled the radio fuse. Neither one work, so it didn't take. It just keeps kicking off the Security light every time I do the step to try to enter programming mode.
TECH Resident
Joined: Jun 2013
Posts: 853
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From: Kernersville, NC
It almost sounds like the BCM is not seeing the expected key resistance and is engaging the security system. Does the car start normally with with the key after the security light goes off? Are the resistor pellet contacts in good shape(in the key cylinder lock)?
Last edited by ACE1252; Aug 28, 2017 at 10:53 PM.
Thread Starter
On The Tree
Joined: Jun 2012
Posts: 106
Likes: 0
From: Carrollton, Texas
Yes, once the Security light goes off, the car will start normally. The resistor pellets on both my sets of keys are in good shape, haven't pulled the cylinder out of the column to check it before, but I have replaced the ignition switch a few months back on top of the column under the dash, and I've also wired in a PassKey bypass (giving the BCM permanent resistance matching the pellet in the key, wired through an on/off switch hidden in the car - did this months ago as well).
TECH Resident
Joined: Jun 2013
Posts: 853
Likes: 32
From: Kernersville, NC
I'm assuming the bypass switch disconnects the key resistor when using it(switching in the resistor). If not, then the resistors will be in parallel which is not good.
If your switch does disconnect the key resistor, have you tried to enter keyless entry programming mode with your bypass enabled?
According to the factory manual, a "new" BCM programs itself to the first resistor value it sees after power up. This value is set for the life of the BCM. Are you sure the replacement BCM saw only your key resistance when it was powered up?
Looks like the BCM can have DTCs. You have to put it into diagnostic mode to pull them. Attached are some excerpts from a 1996 F-Body manual. They might help you nail down the problem.
If your switch does disconnect the key resistor, have you tried to enter keyless entry programming mode with your bypass enabled?
According to the factory manual, a "new" BCM programs itself to the first resistor value it sees after power up. This value is set for the life of the BCM. Are you sure the replacement BCM saw only your key resistance when it was powered up?
Looks like the BCM can have DTCs. You have to put it into diagnostic mode to pull them. Attached are some excerpts from a 1996 F-Body manual. They might help you nail down the problem.
