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?

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