nyurdrms

My keyless entry works for 3-4 days and than has to be reprogrammed to the car. It doesnt take long of course..but it just isn't right having people see a guy physically unlock a car as gorgeous as a C5.

Any thoughts?

And yes, I have replaced the battery in the remote.

Thanks all,

Billdog350

I have the same problem with my 1997 fob. Supposedly this is a sign that the fob is worn out. One suggestion is to take a pencil eraser and clean the contacts for the buttons and battery on the front and back of your fob chip....it never hurts to clean electrical contacts.

Bill Curlee

OK,,,,,,before you spend gobs of cash on new fobs and other stuff, try this:

READ YOUR DTC CODES! Post the results of what codes you find. Make sure that you include all the prefixes and suffixes for the number codes. If you have tons of codes, clear them all and read them again when the fobs fail. That will help us point you in the right direction with out having to guess.

This is the absolute best C5 Code web site!!!

http://www.corvettedoctor.com/Code_Main.html
http://www.corvettedoctor.com/index.html

[www.corvettedoctor.com

Go to “technical data base” and then to “Corvette ECM Computer Codes”. Then select your year car. Read the instructions and then scroll down to the "READ MORE" window to view the code definitions.


If your seeing any "U" series DTC codes,,you most likely have a weak 12 VDC battery. The battery will start the car but the output voltage of the battery will DROP LOW for a millisecond or so (9 VDC) when the starter is first engaged causing the RFA & BCM to clear all of the security code information that it uses to sync the FOBs to the RFA & BCM!!! The modules in you car will shut down if the supplied voltage drops below their designed operating voltage and will not operate again until the correct voltage is present. When you car sits for a day or two, the battery can discharge enough for the output voltage to be low enough that it causes problems. If you drive it daily, it may happen a lot less often.

Allow the car to sit for a few days. Put a volt meter on the battery and have someone start the car. What do you read when the key is first turned! It shouldn't drop below 10.5-11 VDC during the starting sequence. With a new battery, you shouldn't see it dorp much lower than 11.5-11 VDC.
I bet if your seeing the FOBs reset, your also seeing the mileage trip meter, memory functions for ease entry and maybe your average fuel mileage readings reset also.

If all of the above checks out, you could possibly have a bad FOB. Yes they do go bad!! If you do find that you need to order a new FOB,,don't fall into the trap of ordering the WRONG ones. If you have a 97-2000 C5 it will only work with that series FOB. 2001 has it's FOB and 2002-2004 use their own series. Same goes for the Tire Pressure sensors! They are not interchangeable!

Please keep us informed on what you find.

Bill Curlee

zreddog

I guess I should replace mine. When I bought the car the seller bought me a new FOB as they only had 1 old one. I decided to put that one away and just use the old one. Well it quit working a couple weeks ago. I replaced the battery and reprogrammed both FOBs. And it quit working again this weekend. Nothing else in the car has reset and the other FOB is still working.

Off to EBAY I go.......

BTW - I thought the 2000 had the special FOB?

Bill Curlee

Yep you are CORRECT! 2000 was SPECIAL! Sorry for the goof.

BC

Vetteman Jack

Good information. Mine is having the same problem. Going to test this out.

camarossrulz

my 2000 is doing the same thing. sorry about the re-post

muncie21

Any luck guys?

I've replaced my fob battery and charged my car battery, but still the fob only forks a couple of times before it needs to be re-synch'd.

Billdog350

Same problem here. BRAND new red-top, new remote battery, checked remote contacts, checked and cleaned all grounds in electrical system, swapped fobs with backup #2 fob.....same problem. Downright annoying to say the least.

FFIN90

The FOB for my 98 needs to be reset after a couple of days of not driving the car also. I have a new car battery and new FOB battery, I checked the DIC for codes after the FOB quit working and NO codes show up at all, so does this mean it's a strong chance the FOB is on it's way out?

NocarbutaVetteforme

I had the Fob problem above. I r/r'd the battery and same results. Then I found my lost FOB and it worked like a champ. So, now I need to get a new FOB. And wouldn't you know it is a 2000 so I have to get the FOB that is more expensive than the others. My luck continues.

Bill Curlee

Yep,,,try a new FOB!! They do wear out and cause problems. I would try a new FOB before I rip out and replace internal modules!! I have had very good results on E-Bay!

BC

doninfosys99

On my 99 I can reset the FOB and the horn chirps. Can unlock and lock and open hatch. Then 10 secs later the doors lock and the FOB is dead again! Any ideas. No codes on DIC. 3.3 volt battery.

grinder11

Sounds like it's losing its programming to your car. There's a resistor in the Fob that sometimes needs to be resoldered to all its contacts. There is a lot of info here on the forum, complete with pics. This worked for me. However, I'm wondering if you have the 'passive' FOB, where it will lock the car automatically when you get a distance away. This could be why it locks the car, because the car and the Fob cant modulate/communicate with each other. So the car cant find the Fob, or vice versa, so it locks everything. Does your FOB have a switch on it anywhere? The switch itself may have dirty contacts inside the Fob body. If you've already tried all this, disregard, of course. If you haven't, that may well be the problem. If you try to resolder, use a pencil tipped iron, NOT a gun. Using a gun on something this small is like using a chainsaw for brain surgery!!! I'm sure you get my point.....

doninfosys99

When sitting in the car after programming the fob, It works fine for 10 seconds and then quits. Then while starting the engine and sitting in the car and programming it while running , the fob works perfectly until I turn the engine off and then 10 seconds later I lose all FOB function. It seems like when the alternator is supplying power to the car, then, and only then, the FOB works.

jdmvette

BTDT.

A new fob will fix this.

grinder11

What is BTDT???
Been there, done that? Too many abbreviations and acronym's!!!

jdmvette

Been there done that

doninfosys99

1999 C5 When sitting in the car after programming the fob, It works fine for 10 seconds and then quits. Then while starting the engine and sitting in the car and programming it while running , the fob works perfectly until I turn the engine off and then 10 seconds later I lose all FOB function. It seems like when the alternator is supplying power to the car, then, and only then, the FOB works. What causes this?

jdmvette

^ see post 16