DHallworth wrote:Oh yea... one problem I forgot to mention was that when trying to program the new ECU to my car and set the immobiliser up the CPH kept refusing to accept the key code for the car.
After checking with Citroen this morning we are definitely entering the correct key code into Lexia when trying to program the keys but it keeps saying it's failing so I'm looking to change the CPH to try and sort this out.
Were you trying to do the ECU pairing process when it failed, or were you trying to do key programming ? Did it accept the 4 character code and fail later or fail immediately at the point you entered the code ?
I'd try programming the keys (but wait until you get home in case anything goes wrong!

) and if that works it may simply be that the unlocked engine ECU can't be "paired" with the CPH in the normal way, as the immobiliser code in the ROM is disabled.
There are a few different ways that engine ECU might have been unlocked, and the original listing for that ECU was a little vague.
1) Completely unlocked - it will just work right away no pairing needed and can be swapped to another CPH at any point. My Auto Engine ECU that you have is like this. A completely unlocked ECU will have NO immobiliser function - eg you can unplug the transponder antenna around the ignition barrel and the car will still start. (Test after the car has been stopped and locked for 10 minutes as it remembers the last immobiliser unlock for a few minutes)
2) Factory original un-programmed - won't start until you pair it with a Lexia - once you pair it to a CPH it is forever paired to that CPH (unless you send it to an unlocker) and you will have an immobiliser function. This is what I thought you were buying with that ECU.
3) Unlocked and auto-pairing. This is similar to 2 but the ROM code has been rewritten so that it automatically and permanently pairs to the first CPH you connect it to (careful!) without need for a Lexia session. Once it pairs itself it is locked to that CPH and the immobiliser works, similar to 2.
Have you ever done a successful key programming session on the Activa with your Lexia before ? Could the CPH have been swapped before you bought the car therefore meaning the code Citroen has on file is wrong ? If so you could try my old CPH as it has a known code. Bear in mind though that if the engine ECU is indeed fully unlocked you still wont have a working immobiliser no matter what you do...