W220 remote key not working

[pc-uk007]

Hi, Can anyone help me please, i have 2 remote keys one works unlocks car and starts car and id led in fob works, the spare key does not do any of these, i have changed batterys checked voltage all ok here, are there any other checks i have to do before buying a expensive replacement, i also have keyless go that i have one card for that works fine, lookm forward to your comments.

 

[Dieselman]

It sounds like the spare key isn't for that car.
The RF and IR locking and comfort selections are completely separate to the immobiliser.

 

[AndyPCD]

If you get the car on a star machine there is a guided test they can carry out to test the operation of the key.

 

[pc-uk007]

When new batteries to remote are fitted the led should flash when operating the lock and unlock buttons for a period of 6 seconds, this is what it states in handbook to test operation of remote, my one is not doing this so it indicates a problem with remote irrespective weather for remote is correctly coded to my car or not.

If batteries are flat would key still turn in ignition and start car ???

 

[wardpaa]

Unusual for all functions to be lost. If the batteries are flat in the key it should still activate the steering lock when inserted.
Can you remove the PCB from the key case ?

 

[pc-uk007]

Can this be done without damaging infra red at the other end ??? has anybody taken the inners out ???, if so let us know please and i will have a go at doing it.

I have managed to get pcb out of remote the white retaining clip had to be removed after removing battery tray but cannot see any broken solder joints or corrosion, tried also mateing battery tray connection to pcb curcuit board and operating switches still no response from led,

 

[Dieselman]

If batteries are flat would key still turn in ignition and start car ???

Yes. It draws power from the ignition switch via the coil.

Haven't you had the circuit board out to replace the batteries.?

 

[alexander patie]

i think dieselman may have it in post #2! possibly the key has been disabled in the eis as it was once lost?

 

[wardpaa]

LED on the fob should still work though shouldn't it ?

 

[pc-uk007]

I just might have to order a new one from MB.

 

[pc-uk007]

New key purchased all coded from factory, end of thread, thanks for your help, Regards PC.