Citroen XM Forum

Dieselman wrote: Fri Nov 06, 2020 6:43 am 1e trick?

There's a way you can start any XM, Xantia, ZX, Saxo or Peugeot equivalent without the code. It's a 30s work. Can't publish here, we don't want our XMs to be stolen all day around

White Exec wrote: Fri Nov 06, 2020 7:22 am When you say the ECU "has been reverted to standard again", what was done to it earlier?

When failure ECU was modified by a specialist to bypass the immo, an IC was replaced. Didn't work.

Diagbox didn't read the codes

Try using a blink code reader.

Try an ECU reset to factory or an original (unaltered) one with a known code.
The fault is almost certainly not the ECU.