Stereo & Electronics - Can't get car in program mode
08-03-2012, 06:24 PM
I can't get my car to go into program mode. I am trying to get a key fob programmed. I don't know where to start as far as diagnosing goes. I haven't gotten the locks to cycle a single time. I do not have an original to test (broke).
A couple of notes:
-Security light is on and flashing. I suspect that this is a big clue to the problem.
-VATS bypassed via VATS bypass module wired into the PCM.
-TDR is also bypassed as well.
-Steering column has been changed.
-Other than the program mode problem, the BCM appears to be working fine.
Can anyone tell me if it is possible to send the car into program mode in its current condition? I was thinking it may not be a possibility give everything is bypassed on the car. Surely someone else has ran into this. If so, where do I start diagnosing? Maybe there are some diagrams I can use and check voltage at the BCM?
I'm really not wanting to buy a new BCM to have it programmed on the first key cycle.
08-05-2012, 02:08 AM
08-05-2012, 11:07 AM
The security light has nothing to do with the keyless entry system or the factory alarm (if equipped). It only indicates a problem with the passive VATS system (the chip in the key). You can't bypass VATS at the PCM because it is entirely contained in the BCM. A blinking security light means that the BCM can't detect a resistor chip in the key (as opposed to detecting the wrong resistor). In your case, that likely means that the wiring between the column and the BCM is damaged, disconnected or incorrectly bypassed. I suspect that your VATS problem may be related to the programming problem only because the programming procedure involves turning the ignition on and off several times and the BCM is currently not recognizing a valid key in the ignition.
The programming procedure is very sensitive to even the smallest deviation in the steps so you have to follow these steps exactly:
1. Turn ignition from OFF to RUN and back to OFF without starting the car.
2. Remove the RADIO fuse.
3. Turn the ignition from OFF to RUN three times within five seconds and leave it in the RUN position on the last cycle. The car should respond by locking all doors, unlocking the driver's door and releasing the hatch.
4. Press and hold both the lock and unlock buttons on the remote for at least 15 seconds. The car should once again lock all doors, unlock the driver's door and release the hatch.
5. Repeat #4 with any additional remotes.
6. Turn OFF the ignition and replace the RADIO fuse.
08-05-2012, 12:41 PM
Thanks. That is the procedure I am trying to do in reguards to programming mode.
The VATS is bypassed via a VATS bypass module wired right to the correct pin wires off of the PCM. These are the kind of modules primarily used for hybrid cars. It's from my old LT1 truck. I had it, so did not do the resisitors. The column has also been replaced as well. There is no way that it has the correct pellet key in it right now.
If the BCM must recognize a valid key pellet value in order to start the programming mode sequence, I suppose that I could go and buy all possible resistors until I get the right one via trial and error.
Does anyone have a positive answer to whether or not the BCM MUST have the correct pellet value before entering programming mode? Certainly makes sense.
08-05-2012, 02:33 PM
You must have done some additional wiring besides a module connected to the PCM or the car would not start. VATS cannot be programmed out or bypassed in an f-body at the PCM. The BCM controls two separate circuits to prevent the car from starting with the wrong key. It disables the fuel enable signal to the PCM and it removes the ground from the starter relay. You can program the PCM to ignore the missing fuel enable signal but you would have to physically rewire the starter relay ground or the BCM would prevent the engine from cranking.
There are 14 different resistor values used for VATS on f-bodies. There is a list posted somewhere on this forum or you can find it easily using Google. But if you end up installing the resistor bypass, you might as well remove the kit you attached to the PCM as it would then be redundant and could be a potential future point of failure.
08-05-2012, 03:51 PM
That's what I plan on should I wire in a resistor. In addition to the VATS bypass module, I have bypassed the TDR to get the starter to ground. VATS bypass for the pellet, TDR bypass for the starter ground.
I still have a question, Does the BCM require the correct pellet value in order to go into programming mode? If anyone knows a definite answer to this, it would be very much appreciated.
08-05-2012, 05:55 PM
I checked the factory service manual and there is no mention of VATS in the keyless entry diagnostics section. It sounds entirely reasonable that it might not program without the correct key but I have no proof.
BTW, the Theft Deterrent Relay has nothing to do with the starter - it only controls the flashing of the lights for the alarm system. You must have added an unswitched ground to the starter relay (rather than bypass it) to get the car to start.
08-05-2012, 06:09 PM
This is what I did. Second paragraph under the "what to do" headline has the schematic that I used to do this. Basically just putting the yellow and purple wires together.
In any event, I think I'm going to give the resistors a shot and see if I can get it to work that way. It sure seems logical and its certainly worth a shot.
Thanks for the info, man.
08-06-2012, 07:40 AM
Interesting! I'll have to email Rob to let him know that his information is a little misleading. He is correct in referring to the relay as the TDR for pre-96 models (those without a BCM) but 96 and later models with BCM changed the wiring so that the BCM controls the starter relay and the TDR controls only the flashing of the parking lights. It's not a big deal since the wire colors are the same in either case.
However, nowhere did he suggest splicing the yellow/black wire to the purple wire. He only says the yellow/black wire needs to be permanently grounded. The purple wire may show ground if you just do a quick test but it is actually the coil supply for the starter solenoid. You should check your wiring and correct it as necessary so that the yellow/black wire goes directly to a good chassis ground.
08-07-2012, 10:23 PM
I dunno. I did that when I changed the engine along with the harness. Whatever it was that I did allowed it to work again. That's all I was worried about at the time and it hasn't had any problems (other than this programming thing) That's been 4 years ago since I did that. I'll go back and re-check what I did. I remember distinctly doing something with the purple wire. If that wasn't supposed to be touched... well uh oh.
Thanks for the info again!