Citroen Relay 2020 issues

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bennyh
Posts: 3
Joined: 13 Oct 2025, 15:05

Citroen Relay 2020 issues

Unread post by bennyh »

Hello, newbie here.
I'm having a problem with diagnostics access.
Vehicle is Citroen Relay 2.2 2020
The best I can get is access to a few modules, but crucially NOT the engine ECU
I have tried the Lexia 3 with and without S2179
I have tried VCX-SE interface today (same result as Lexia) (I think it has dynamic pin allocation)
Tried some generic commercial offerings like Topdon but got nowhere at all.
I didn't get this far until I re-wired the S2179 according to the PSA-diag forum. (I tried asking for help there but got nowhere)
I had a glimmer of hope when I very briefly got through to the Engine ECU after running the engine and stopping it. It then kicked me out. (Delphi 7.1_F module)

What is going on here do you think?
Wiring problem?
Software security gateway?
Thanks in advance
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mickthemaverick
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Re: Citroen Relay 2020 issues

Unread post by mickthemaverick »

Purely partially educated guesswork: Since you are basically having comms problems with different readers I would suggest the problem may be the wiring of your OBD2 socket. You may have a bent or misplaced or even broken pin inside the socket so I would check that out before going any further. :)
I used to be indecisive, now I'm not so sure!
I used to ride on two wheels, but now I need all four!
bennyh
Posts: 3
Joined: 13 Oct 2025, 15:05

Re: Citroen Relay 2020 issues

Unread post by bennyh »

mickthemaverick wrote: 13 Oct 2025, 15:33 Purely partially educated guesswork: Since you are basically having comms problems with different readers I would suggest the problem may be the wiring of your OBD2 socket. You may have a bent or misplaced or even broken pin inside the socket so I would check that out before going any further. :)
Thanks Mick,
Apart from inspecting the connection hardware, is there anything else I can do to investigate? I don't own an oscilloscope!
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mickthemaverick
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Re: Citroen Relay 2020 issues

Unread post by mickthemaverick »

You need to get a global scan done but with the comms errors you have I appreciate that is easier said than done. Once you are happy about the OBD2 socket and the wiring and connectors between it and the ECU then I fear that the problem may be within the ECU, possibly as the result of dampness so a thorough drying (eg. hairdryer) of the Engine fuseboxes and associated hardware may help. :) Once done then do a BSI reset following the procedure in the link below and then try scanning again.

viewtopic.php?p=601679#p601679
I used to be indecisive, now I'm not so sure!
I used to ride on two wheels, but now I need all four!
bennyh
Posts: 3
Joined: 13 Oct 2025, 15:05

Re: Citroen Relay 2020 issues

Unread post by bennyh »

Alas, no dice
My VIN is incorrectly listed as 2001 vehicle in an online database I searched. Does that matter?