Reprogram Key Fob

dwhults · September 30, 2008

Ok I just bought this truck on Friday. The battery in the remote was weak so I changed it. Now it doesnt work. I held down LOCK and UNLOCK and it did not reprogram. I tried several other methods including on-off-on-off-on, holding the UNLOCK switch, etc. The only thing that seems to work is jumping pins 4 and 8 on the OBDII port. That locks and unlocks the doors signaling the reprogram mode.

The problem is that I cannot reprogram the remote. I hold LOCK and UNLOCK for 15 seconds while the jumper is in and nothing happens. Can someone help me?? I tried using my Actron CP9190 scanner but no go. I really dont want to go to a dealer everytime my remote battery dies. Help!!!

1999 GMC Yukon SLT.

jdawg1234 · September 30, 2008

This may be a dumb question, but did you put in a brand new battery?

just wondering because it shouldn't have reset, it should still work. I have had to replace 10+ batteries in all the trucks and cars we have owned and never had this problem.

dwhults · September 30, 2008

This may be a dumb question, but did you put in a brand new battery?
just wondering because it shouldn't have reset, it should still work. I have had to replace 10+ batteries in all the trucks and cars we have owned and never had this problem.

Yes it was new. I even put the old one back in and no go. Im stumped, can someone help me out?

2000DV4.8 · September 30, 2008

'Nother dumb question: You sure the battery's not in upside down?

Can't hurt to double check.

dwhults · September 30, 2008

'Nother dumb question: You sure the battery's not in upside down?

Can't hurt to double check.

Wow I think it was upside down . I will check after work and let you know...

DofD · September 30, 2008

I've changed the battery before, taken them apart to clean them, and never had an issue with needing to reprogram.

dwhults · September 30, 2008

Worked! Had the battery in backwards but I had to reprogram with jumping the OBD but it works! Thanks!!

2000DV4.8 · October 1, 2008

Worked! Had the battery in backwards but I had to reprogram with jumping the OBD but it works! Thanks!!

Cool! I've done it before, that's why I thought to ask.

jimmycaps · May 27, 2010

I have done all of these steps above. I have connected port 8 to 4 and can get the doors to lock and unlock, but when I press the lock and unlock button on the key fob, nothing happens. I have also tried turning it on and off and on and off while holding the unlock button and then pressing lock and unlock simultaneously on the key fob without any luck.

I have tried this with one original key fob and then I got another used key fob for another vehicle on ebay and that one doesn't work. Both key fob batteries work because I tried them in key fobs for other cars.

What could be my problem?