BenzWorld Senior Member
Date registered: Jul 2004
Vehicle: 00 C-230, 04 C-240
Location: Lancaster, CA
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
The key FOB works on radio Frequency (RF) and InfraRed (IR). Both, RF and IR lock/unlock the car. But, the ignition only works with IR. I have had a problem with my key FOB where the lock/unlock worked fine, but the IR did not for starting the car (weak battery, dirty IR window on key and ignition).
Swap the batteries in the key FOB. Also clean the small, red windows on the tip of the key and the ignition switch on the dash.
If the key FOB is still not working, order a new one from Mercedes.
Replacing the ignition circuit is your last resort.