Citroen Relay P22DTE 2017 - Immobiliser fault after ECU replacement #
Posted by Ryan Cake on June 29, 2020, 3:41 pm
Year of Manufacture: 2017
Engine Size and Code: 2200 P22DTE 4HH
( Optional ) ECU Type: SID208
( Optional) Fault Codes: U0426: wrong immob. code from eng ecu to bsi
……….FAULT: sporadic rough running and occasional cutting out.
……….INITIAL INVESTIGATION: Various fault messages on the dash which would clear on some restarts... When with us doing diagnostics the problems worsened until it wouldn't start/crank *but the immobiliser light would extinguish*. OBD wouldn’t connect to engine ECU and we had strange powers on wiring between fuse box and ECU. If the battery was disconnected and re-connected and the engine relay unplugged and back in it would start and run fine for 15 secs then diesel knock once and stall.
………DIAGNOSIS: After some wiring checks we confirmed the engine ECU was faulty, sent it off for testing and came back as un-repairable, they opened it and found extensive water damage.
……….PARTS: New ECU fitted and coded by Airbagman - *the immobiliser light stays on the instrument cluster* but it started on first attempt, but wouldn't switch off when key turned to off and removed from barrel. It then wouldnt start or crank at all after this.
………CODE: We have an immobiliser fault in the BSI – U0426: incorrect immobiliser code sent by the engine management ECU to the BSI. (code was present on both old and new engine ECU).
……….MORE INFO: Airbagman is convinced it’s an issue with BSi or wiring between the two and not the engine ECU. If the engine relay is removed and refitted the vehicle will crank once only and not start…
If we deplete the battery voltage, the *immobiliser light extinguishes* and the starter engages on every occasion.
If we then use a battery charger we can get the van to start and run/rev/drive. But not switch off as above – this will only happen once, we need to deplete the battery again.
Does anyone have any ideas at all?