Key Fob Reset question

[jimmycaps]

I need help with reprogramming my key fob to a 1999 Chevy Tahoe.

I took it into get my a/c fixed and they replaced the compressor. When I got it back, my key fob didn't work. It wasn't working very well before I took it in, but now it doesn't work at all. So initially I replaced the battery, but that didn't work.

Then, I looked up a number of ways to reprogram the key fab. I tried hooking up ports 8 and 4 on the OBDII. This resulted in the door locks locking and unlocking quickly, but when I pressed lock and unlock simutaneously on the key fob, nothing happened. http://www.programyourremote.com/classified/DisplayAd.asp?id=378

I also tried turning the ignition on and off and on and off while holding the unlock button on the door and then releasing and pushing lock and unlock on the key fob simutaneously for 15 seconds and that didn't work.

I have checked and the batteries are in correctly and I know they work because I have changed them with key fobs to other vehicles and they work.

Any ideas?

 

[josetizapan]

Maybe you got a bad key fod you could go to your local junk yard and get one for $20 thats how much i got mine here where i live.

 

[jimmycaps]

I did get a new key fob and this one doesn't work either.

Any more ideas?

 

[hemihemi]

I did get a new key fob and this one doesn't work either.

Any more ideas?

try disconnecting battery for 10 - 15 minutes to reset computer, sometimes that works wonders.

 

[jimmycaps]

Key Fob will reset and only work when the engine is running or when Accessory poweron

I think I have been able to reset the key fob correctly, but it only works when the tahoe is running or when the key is turned to ACC. Once I turn the car off, the fob works maybe 1-2 times within 1 min and then won't work again. Then, I have reprogram it all over.

It seems like it is an electrical problem and not the key fob. Any ideas of what to do?

 

[SunlitComet]

On the first attempt with pins 4-8 did you hold both for about 15 seconds or let them go right away. The first one takes longer to lock in while additionals happen quickly.

 

[jimmycaps]

Yeah, I held the buttons for a long time. I can get it to work consistently, but only when the key is turned to on or ACC. Once I take the key out of the ignition, the fob works for maybe one or two presses, and the fob doesn't work at all.

I don't know if wiring to the receiver is bad or something like that?

The fob works with a power supply.

 

[SunlitComet]

Try this:

1. Resynchronization may be necessary due to the security method used by the RKE system. The transmitter does not send the same signal twice to the receiver.
2. The receiver will not respond to a signal which has been previously sent. This prevents anyone from recording and playing back the signal from the transmitter.
3. Resynchronization will be necessary if any of the following are true:

o You change the transmitter battery.
o You disconnect the vehicle battery.
o You push the transmitter button 256 times out of the range of the receiver.

4. In order to resynchronize the transmitter with the receiver, perform the following steps:

4.1. Stand close to the vehicle.
4.2.
The door locks should cycle to confirm resynchronization. Simultaneously press and hold the LOCK and UNLOCK buttons on the transmitter for seven seconds .

 

[jimmycaps]

I did this already and it doesn't work. The key fob only works when the engine is on or the ignition is in ACC mode. Then, once I synch it, it works fully until the car is turned off. Then it doesn't work at all and I have to repeat the process.

 

[SunlitComet]

I have some diagrams that could help further with what sounds to be a power supply issues but I need to know if you have the base option or luxury option.