I just bought a 2004 coupe that has two fobs, both marked #1 on the back. One works and one does not, even after replacing the battery. I matched them per the owners manual and the one that had been working "learned" but the other one did not. Must the second fob have a number 2 on the case to work? I previously owned a C6 and the fobs were marked 1 and 2.

rocklin-ron

 

My C5 fobs are marked 1 and 2 also. Someone picked up another fob. You can sync the other to your car I believe. I had to re-sync mine when I put in new batteries. I remember it had something to do with holding down the buttons on the fob and the lock and unlock buttons on the door until the horn sounded. You should be able to look it up here easily enough

 

The transmitters are the same. The only difference is the plastic is numbered 1 or 2 to help keep them identified if you are using memory settings. Whichever one is trained 1st will be number 1 to the car.

To train them I copied some things out of the owner's manual.

FOB TRAINING: This option allows you to match the RFA transmitter(s) to your vehicle.
You can access this option by pressing and holding RESET for three seconds while you are on the blank page at the end of the OPTIONS menu.
The message FOB TRAINING will be displayed. See “Matching Transmitter(s) To Your Vehicle” in the Index for more information.

Matching Transmitter(s) To Your Vehicle
Each key fob transmitter is coded to prevent another transmitter from unlocking your vehicle.
If a transmitter is lost or stolen, a replacement can be purchased through your dealer.
Remember to bring any remaining transmitters with you when you go to your dealer.
When the dealer matches the replacement transmitter to your vehicle, any remaining transmitters must also be matched.
Once your dealer has coded the new transmitter, the lost transmitter will not unlock your vehicle.
Each vehicle can have only three transmitters matched to it.

To match transmitters to your vehicle:
1. Turn the ignition key to ON.
2. Clear any warning messages on the Driver Information Center (DIC) by pressing the RESET button.
3. Press the OPTIONS button on the DIC several times until the blank page is displayed, then press and hold the RESET button for two seconds.
4. When the message FOB TRAINING is displayed, push the RESET button once. The message HOLD LK + UNLK 1ST FOB in the DIC will be displayed.
5. Press and hold the LOCK and UNLOCK buttons on the transmitter simultaneously for 15 seconds.
6. When a transmitter is learned (matched), the DIC will display FOB LEARNED and then prompt you to learn the next transmitter.
7. Repeat Steps 5 and 6 for each additional transmitter.
8. Remove the key from the ignition.
The programming mode will shut off if:
-You don’t program any transmitters for two minutes.
- You take the key out of the ignition.
- You have programmed three transmitters.

Note that after changing the battery in the fob it will need to be resynced. Usually not retrained to the car. I copied more from the owner's manual below.

Resynchronizing Your Transmitter
Your RFA system uses a continually changing code for increased security. Normally, the receiver in your vehicle will keep track of this changing code. If your vehicle does not respond to your transmitter, do the following to determine what’s wrong:
1. Get closer to the vehicle and try pressing a button again. Your battery may be low (If so, see “Battery Replacement” in the Index).
2. While standing close to your vehicle, press the LOCK and UNLOCK buttons on your transmitter at the same time and hold for seven seconds. This will attempt to resynchronize the security code in your RFA key fob transmitter.
3. When resynchronization is achieved, the horn will chirp.

Loss of synchronization will occur after transmitter battery replacement or disconnection of the vehicle’s battery.
If attempts to resynchronize your transmitter to the vehicle are not successful, you may need to match the
transmitter to the vehicle. See “Matching Transmitter(s) to Your Vehicle” in the Index.

Good luck.

 

Neither resynching nor matching worked. It may be a bad fob. At least both keys and one fob work. I can live with that as I am the only driver. Thanks for the responses.

rocklin-ron

 

You can buy a like-new replacement FOB online, like I did, for about $30 or less through Amazon. Also, check inside the bad FOB. It could just be a loose solder point on the circuit board. You can always save the bad FOB's shell casing as spare replacement in case the other one breaks or cracks. Did you know that you can also get OEM replacement "shell only" FOB casings online? They're out there for about $5.

 

I agree. You can find them pretty cheap if you shop around.

A couple months ago I bought 2 new fobs (a #1 & a #2) for $27 ($13.50 ea.) from a vendor on the auction site. Although I don't think they are GM OEM fobs, when I look at them side by side with the GM ones, I can't tell the difference and they work correctly.

If you find you want another one there are some pretty good deals out there.

Good Luck.

 

Thanks for the heads up. I just bought a new number 2 fob on eBay for $12.97 with free shipping. I had no idea they could be purchased this cheaply.

rocklin-ron