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CLK430 ignition key problems

8K views 4 replies 2 participants last post by  keyhole 
#1 ·
My wife has a 2001 CLK430. It has two keys [one is a duplicate]. One key will no longer unlock the doors but will start the car and the other one will no longer start the car but unlocks the doors. What can I do to correct this? Thanks from Kona, Hawaii.
 
#4 ·
Here's the latest:

I tested all the batteries [brand new from Walmart] with a voltmeter and got between 2.84 and 3.01 volts. I bought 4 more at Lowe's and got 3.28-3.31 volts. I put the latest batteries in. Now one key unlocks the doors and starts the car. The other key unlocks the doors but does not start the car. That key goes in the ignition but will not turn. What needs to be done to get that key to work? Thanks.
 
#5 ·
The batteries are to power the RF (FM) transmitter in the key fob. That is only used to remotely operate the door/trunk locks, and has nothing to do with the ignition switch. You can start your car without a battery in the key fob.

The key fob also contains an IR transmitter/receiver, and a computer chip. When inserted into the ignition switch, the key is supplied with voltage via an induction coil in the switch. Data is exchanged via the IR Tx/Rx units for the purpose of Drive Authorisation. If OK, the car may be started.

In other words - your key that will not start the car is damaged in some way. The IR system is not working. You will probably have to replace the key.
 
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