G Klasse Central Locking Failure

Sounds familiar. Something similar happened on my G Klasse. First, check the wiring harness where it passes from the body to the door. Those wires flex when you open and close the door, and they're known for breaking. Also, double-check the connector for corrosion. Does the security system seem to be behaving normally otherwise? Any issues with other electronics?

Thanks, that's helpful. Where is that wiring harness located? Inside the door panel, or visible when the door is open? Also, how do I check the connector for corrosion? Any tips? Everything else seems to be working fine. No other weird electrical issues that I've noticed.

The harness is usually between the door and the body, covered by a rubber boot. Peel back the boot to inspect the wires. As for the connector, look for any green or white powdery buildup on the metal contacts. If you find corrosion, try cleaning it with electrical contact cleaner, but be careful. Given the symptoms and the error code, it's probably best to have a workshop take a look. They can pinpoint the exact fault with their diagnostic tools. You mentioned a defective wire or plug, this sounds very likely.

Appreciate the advice. I found the corroded connector and tried cleaning it but no luck. Ended up taking it to a shop as you suggested, and they confirmed it was a faulty plug connection, just like I suspected. Repair cost 95€. Thanks again for pointing me in the right direction!