My brother has a 2002 C240 Automatic sedan.
He has I believe 2 regular Key Fobs and one Valet key fob.

He changed the battery on both Regularly used key fobs. Now after he changed the battery, both remotes stopped working and would not lock or unlock the car. Also now only one regular remote and valet key fob can start the car. This is a very wierd problem. I told him to disconnect the vehicle battery for a few minutes and then try again which did nothing.

Would this possible be related to old or bad key fobs? Price wise, what would he be looking at for 2 keys being programmed and replaced?

__________________
2001 E55

2001 E320 Sedan

2001 Subaru Legacy

2006 SLK280

2016 Subaru Outback 3.6

hmm, Try re-training them to the car first if there's a simple way to do that. It should outline it either on here, your user manual or someone can chime in on how to do it.

__________________
hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

So they were working OK before the battery swap? Are the new batteries installed correctly? Are you sure the new batteries are any good? Check the simple stuff FIRST! Don't start chasing non-existent problems.

FYI, the key batteries have nothing to do with starting the engine.

Thanks guys. I asked my brother if he installed the batteries correctly and if he got the right ones and he assures me he did. So far there is still a problem I will do some more research and worse case scenario I will bring it in to the Dealer and have it diagnosed.

__________________
2001 E55

2001 E320 Sedan

2001 Subaru Legacy

2006 SLK280

2016 Subaru Outback 3.6

u solve your problem?

__________________
My Cars
Mercedes CLS
Mercedes C-Class W203 - All time favorite

R.I.P.
Mercedes C-Class - W202 Lemon
Mercedes ML - Warrior
VW Jetta – Worst Car I ever owned - Alot of problems