Keyless entry failure?

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,580
1,834
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Mid Michigan
On a 2003, what would cause the keyless entry to no longer work? Neither fob will lock or unlock doors or set alarm.

Fob batteries are new, all fuses are good. Im not sure what module operates the keyless system.

DDM fail?

I did replace my cluster last year with another out of a less-optioned truck (the donor for the 1/2 ton, if you remember that), bc my original cluster went multilingual on me, and I dont speak/read French or Spanish. Im pretty sure everything else on the truck worked as it should, though.
 

Cougar281

Well-known member
Sep 11, 2006
1,805
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63
St Louis, MO
Pretty sure the keyless receiver is in the PDM. Maybe it had a stroke and forgot your fobs. Have you tried reprogramming them?

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TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,580
1,834
113
Mid Michigan
Fob 1 wouldnt program, Fob 2 did. Fob 1 failing is probably what failed the system. Onto Ebay to find a new one. Thx Coug.
 

DAVe3283

Heavy & Slow
Sep 3, 2009
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Boise, ID, USA
Be very careful with eBay and Amazon fobs. They are all Chinese clones, and have the same crypto key in all of them. The only thing that is different is what position in the rolling code they are in.

I discovered this the hard way when my neighbor would leave for work and it would unlock my truck too. Asked and found he had a cheap replacement fob like me. Started testing out and I could unlock my 2 rigs, my neighbor's truck, and my brother's truck using any of the fobs. Just had to try 5-6 times to get the rolling code aligned.

After that I ponied up for genuine GM fobs and now my truck doesn't listen to the generic clone. Wasn't worth making it that easy to get into IMO.

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DAVe3283

Heavy & Slow
Sep 3, 2009
3,724
292
83
Boise, ID, USA
Tom, what probably happened is your truck battery went dead or the fobs battery was disconnected. That causes the rolling code to get out of sync. You can either re-learn the fob as you did, or hold down both lock and unlock buttons on the fob at the same time. That causes the fob to rapidly send out codes and the truck can re-sync with the rolling code.

It usually takes 20-30 seconds then the truck will start responding to the fob again. I usually do this because it's faster than re-learning the fobs.

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TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,580
1,834
113
Mid Michigan
Thanks.
I have to admit, I cannot remember ever having a issue with the fobs on this truck, even when the truck batteries went dead over the winter years ago.
I had completely forgot about the relearn procedure. I just figured the KE module had died after 20 years.
 

BrandonLLY

Member
Apr 23, 2014
116
8
18
Mine went out on my 04. Bought one of these about 8 years ago and running strong still.




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