This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Posts: 2
Joined: 20 Oct 2022, 19:32


Post by Philipopo »

Does anyone knows the cause of this 2 fault marked here please. This is for Citroen C4 B7 with automated manual gearbox. I had replaced the engine, but has refused to start up.
User avatar
Forum Admin Team
Posts: 37780
Joined: 15 Sep 2015, 19:38
x 5820

Re: Help

Post by GiveMeABreak »

The gearbox ECUs on these vehicles can also be paired to the engine ECU. If you have changed to a different engine ECU or the engine is not identical, then it can stop the car from starting as you can see from the diagnostic information - the engine ECU is not authorising the starting of the vehicle as it's getting the request from the gearbox ECU, but not the authorisation.
Please Don't PM Me For Technical Help

User avatar
Forum Admin Team
Posts: 9134
Joined: 09 Nov 2005, 23:03
x 847

Re: Help

Post by xantia_v6 »

I would expect that live data in the gearbox ECU will give the cause for it not authorising the engine start.