Smart Key Problem
I got a problem with using my smart keys and while I have found a great many posts that talk about smart key issues, I have yet to see one that discusses the specific issues I am having. Here is what I know:
Info: 2003 C32 4-Door Sedan
Symptoms: After the car sits for a while 1+ hours the smart key fails to unlock/lock the car. After manually unlocking the car and placing the key in the ignition, regardless of whether I started the car or not, the key will work once again.
Diagnosis:
1. At first I thought it was the batteries in the key so I checked them. I also tried my spare key....the problem persisted with both keys, which points to the problem being in the car.
2. I thought I had an issue with the battery in the car. I had the charging system tested and it seems to be working fine.
3. I thought there could be a draw or short on the battery, so last night I record the battery voltage when I parked the car 12.87V, this morning I went out and checked the voltage to see how much it had been drained but it showed 12.47V.
4. Since the smart key works part of the time, I doubt it's the IR or RF antenna.
My theory:
There is something wrong with the EIS or the receiver in the the car? Has anyone else experienced something like this?
I tested to make sure both the IR and RF worked, testing the IR by lowering the windows using the key, and the RF by unlocking the car with the key in my pocket and ir blocked.
after a specified amount of time (1 hour), the car goes into a "sleep" mode. IF thats the case, then yes its on the cars end. if both keys are doing that and its consistently 1 hour after, then i would say it is definitly on the cars end.
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