Citroen XM Forum

My 1992 XM V6 24 is currently in Bad Camberg, Germany, immobilized when the battery completely ran down earlier this winter. I've already made one attempt to start the car last February and was unsuccessful. As I recall, both red and green lights were lit after I put in the correct 4 digit code, but the car did not start. I'll have another opportunity to get the car started on 8 June when I'll be in Germany again. My goal is to start the car and get it to Rotterdam where it can be shipped to me in California. Is there anyone in these forums who can explain to me a clear course of action to get the car started? I will be purchasing a new battery and will have this installed before I begin any attempt to start the car, something I did not do during my last attempt.

Any technical help to get the car started would be greatly appreciated. The car is actually parked at Auto-Kaiser Peugeot/Citroën in Bad Camberg, so some technical assistance is available. But none of the mechanics at Auto-Kaiser have any experience with the anti-theft system installed in the XM. The XM is as foreign to them as any other contemporary mechanic today.

Send a personal message to citroenfa a member on here.
He is in CA with recent experience of red/green lights on a V6.
He got sent quite a bit of information on the V6 including circuits.
He may be able to give advice and documents for you to take with you.

John

I know California is a huge place, but wouldn't it be great if these 2 guys met and formed a Citroen friendship through our forum.

If red and green lights are on simultaneously it generally means that the keypad cannot communicate with the ECU. This is often because one of the supply lines to the ECU is not present.

The loom is fairly simple for this, check the relay connections in the front of the underbonnet ECU box and also the black 5 pin plug that only has green wires going to it which should be in with the ECU's themselves, clean all contacts and try again.

If no joy check the brown plug which is under the LHM tank to make sure all contacts are clean and there is no broken wires.

Also worth checking the plug on the Keypad itself, this is fairly delicate.

A lot of things will bring both lights on but there are not many places the problem could be thankfully.

D

The best solution would be an unlocked spare ECU. Plug it in and off you go.
Alternatively you can put your ECU in a similar, working car, enter the code, start the car and unplug the keypad, thus unlocking your ECU.
Make sure your car has the keypad unplugged when using an unlocked ECU.

Maybe it's been written up before, but it would be useful if a definitive set of steps to follow for unlocking/unblocking an ECU-keypad combination could be posted, along with any variations for model type.

Good few keypad system failures reported lately, leaving cars immobilised.

This method is for working cars only!
Punch the code, green light, start the engine.
Leave the engine running and unplug the keypad.
Stop the engine, start again to check.
Never reconnect the keypad again.
That's it!
I have personally tested the method on several XM and Xantia(e) but never bothered to check ECU types/numbers
As far as I recall it works on V6 PRV, Turbo CT, 2.0 16v, Xantia 1.8 and 2.0, both 8 and 16v.

Do not forget to paint the code number on the ECU as well.
Otherwise the car will be totally code locked if the keypad gets plugged back in and ignition turned without a known number.

It should be pointed out that an unlocked ECU will still not start the car if there is an underlying wiring problem (which is the most likely cause of the correct code not being accepted).

It has also been said that this method does not work on all ECU versions, the Xantia 2.0 TCT being an example (and probably the same ECU as a Mk2 XM TCT). I am fairly sure that it does work on an ES9 V6.