Looking at buying a 2000 C5 and the guy that owns the car says the key fob stopped working, he replaced the batteries and it still doesn't work?
I have a 99 GM and I think my batteries are original and still work. Can the key fob loose it memory, would it have to be programmed or is there more to this.

 

Try the following in order:

Test the FOB batteries to insure they are good. Even newly purchased batteries can sometimes be bad.

Clean the battery contacts inside the FOB. A typing eraser, if you have one, works well for this.

Make sure the battery contacts inside the FOB are making good contact with the battery. Sometimes the contacts may need to be bent slightly.

Next, first try resynchronizing the transmitters as shown in the procedure below. If this doesn't fix the problem, then try the relearn or matching procedure below. Both of these procedures can be found in the owner's manual under Remote Keyless Entry:

Resynchronizing Your Transmitter

Your RKE 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 RKE transmitter.

3. When resynchronization is achieved, the horn will chirp.


Matching Transmitter(s) To Your Vehicle
(NOTE: You can perform the matching procedure on your own and do not need to go to a dealer to have this done.)

Each remote keyless entry 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.

If you find that you repeatedly have to resynch or match the FOBs often, have the car's starting battery tested. See Bill Curlee's reply in the following thread:

Keyless Entry Always Needs to be Reset

If after having tried all of the above and you still have problems with the FOB, then it likely is bad and may need to be replaced.

HTH and good luck!

 

Thanks for the info.
Marc

 

If the above instructions don't fix the problem, it's probably a bad receiver in the door control module.

 

you change batteries and you have to reprogram

 

Seems to be a problem with the 2000 models, he just emailed me and said both fobs stopped working after he replaced the car battery last fall and the fobs last a few days and loose the programming?

 

Good information here. Keeping it for future reference.

 

Seems ironic both fobs would go bad after a battery change but has anyone else resolved this problem other than replacing the fob?

 

I had to replace my fob when I purchased the car a few years ago

 

I just got my car back from the body shop and my fob doesn't work...it worked before hand. Hopefully one of those fixes will take care of it.

 

Just held the "lock" and "unlock" buttons simultaneously and it now works again!
Now I won't look like a smuck when I have use the key to unlock the car.

 

The GM Service Manual contains a number of pages of diagnostic procedures on the Remote Keyless Entry. Without going through these diagnostics, I don't think one can totally rule out any number of things just yet. However, as the seller seemed to indicate that the RKE works for a short while after performing the resynch/reprogramming procedure, it appears that perhaps the following may be working at least part of the time:

• The FOBs are transmitting to the Remote Control Door Lock Receiver (RCDLR or the Remote Function Actuator, RFA as it is often called especially for earlier model years).
  
  
• The RCDLR is communicating with the Body Control Module (BCM) and the left and right door control modules (DCM).

With the above in mind, the symptoms at this point seem to me to be pointing to one of several things and this is where I would start looking. These things can cause the FOBs to lose communications and/or become out of synchronization with the receiver.

• A weak starting battery or bad connection there. Check the car's battery terminals for corrosion and to insure that they are properly tightened, but not over tightened. Test or have the car's battery tested under load. Again see Bill Curlee's posts in the link to the thread that I posted above. Here's the link again:
  
  Keyless Entry Always Needs to be Reset
  
  
• The car is not being driven often enough to keep its starting battery at a sufficient state of charge to keep it from dropping momentarily on start up to around 9 VDC or below. Again see Bill Curlee's posts in the above link.
  
  
• Something may be causing an excessive current draw on the car's battery once the car's ignition has been shut off. This excessive draw may be just enough that the battery still has sufficient charge to start the car but not enough to keep it from dropping momentarily to 9 VDC or below. See Bill Curlee's replies in the following thread:
  
  battery drain possibly?

Again, these are just guesses on my part based on what has been presented in your posts/replies above. You may want to run the car's onboard diagnostics to see if there are any diagnostic trouble codes (DTCs) that might lead one to other possible causes. Bill Curlee tells how to run the onboard diagnostics in the first thread link that I posted above.

If you run the on-board diagnostics, record them along with their prefixes and suffixes as Bill mentions. Then post them along with the details above in the C5 Tech section of the Forum. Bill is one the Forum gurus when it comes to the C5's electronics and electrical system. By posting there, hopefully he may see it and offer other suggestions and recommendations.

HTH

 

My fobs are doing the same thing. Fob1 will only work for a few hours and then requires re-synching. I've done this holding lock/unlock and also via the DIC. Fob2 won't sych at all (used to work fine).

I've put new batteries in both fobs. Going to replace the car battery soon and see if that helps.

 

Well the car is a pretty nice so it looks like I will buy it and see if I can get them working after the purchase.
From all the back posts I've read it seems to be a common problem, a lot of people have cured the problem with a new fob but I will run the diagnostics to check for codes.

 

my fobs lose their memories after 30 seconds!

the only option for me is to try a brand new fob but i think it's a waste of money because the problem is caused by something else.

 

I'll sell you mine. J/J

 

sweet, when did you get a 2000?

 

Hey I didn't say they would work, just that I would sell them to you. LOL

 

how bout a trade for my stock rear plastic endlinks?

if you're nice i'll even throw in the stock steel front ones.

 

Looking for new Oem part number 19151480 keyless entry receiver for 2000 corvette so my key fob can be programmed.