DS5 Keyless Entry Failure

Sounds like a classic Citroen DS5 wiring fault. The door handle electronics are notoriously sensitive. Have you checked the wiring loom where it passes from the body to the door? That's a common spot for breaks and chafing. Also, give the connector block for the door actuator a wiggle and see if anything changes. Could be oxidation causing a bad connection. Do you have access to a multimeter?

Cheers for the quick reply! Yeah, I had a quick poke around the wiring loom, but didn't see anything obvious. A wiggle of the connector block didn't seem to make a difference either. I've got a multimeter somewhere, but to be honest, electrics aren't my strong suit. Any specific pins I should be testing, or a particular voltage I should be looking for on that connector?

Without the specific wiring diagram for your DS5, it's tough to say exactly which pins to test. You'd be poking around blindly and could potentially cause more problems. Given the symptoms and the fact that it's logging an error, a trip to a workshop might be the best bet. They can pinpoint the exact fault with their diagnostic tools. I still reckon it's a cable or plug connection that is faulty. They'll likely confirm the same after having a look.

Okay, fair enough, sounds like I'm out of my depth! Bit the bullet and took it to the shop. You were spot on, turns out it was a corroded connector on the door actuator. They cleaned it up and the keyless entry is working again. Bill came to 95€, which isn't too bad all things considered. Thanks for the advice!