Jumper control unit communication error

Sounds familiar. I had similar nightmares with my old Volvo, although it was a diesel. Constant data link errors showing up on the diagnostics. Turns out, on the Volvo, it was corrosion in the plug connectors for the ECU. The car diagnostics were showing a bunch of weird diagnostic trouble codes. Have you checked the pins and wiring harness for the Citroen? Even a slight connectivity issue can cause havoc and trigger the software glitch.

Corrosion, huh? Interesting. Where exactly on the ECU did you find the corrosion? Was it obvious, or did you need a multimeter to track it down?

Yeah, it was mainly the main ECU connector, but also check the ABS module connections. I know, different car, different brand, but still worth checking. Look closely at the pins themselves; you might need a magnifying glass. Honestly, if you're not comfortable probing with a multimeter, might be worth a trip to the workshop. I ended up having to get a new connector and some wiring spliced in. It may be more than a software glitch.

Cheers for the advice! Took it to the workshop, and you were spot on. Turns out it was a dodgy plug connection to the ECU. Cleaned it up and replaced the connector. Cost me 95€, but everything's running smoothly now. Appreciate the help!