C4 Parking System Fault

[gosnoid72]

When I start the car, without the parking assist system disabled, I get a fault message on the dash 'Parking Assist System Fault' or something similar. Last night I disconnected all eight sensors, thinking that by removing a faulty sensor, it would remove the fault. It didn't make any difference, so I'm wondering if a disconnected sensor is actually a system fault? If so, can I short out each plug to make the system think that the sensor is fitted? I've read the other posts about feeling the 'buzzing' sensors, if they're working and I'll try that (does that still apply if the system is in fault?). I assume that the system is split and the rear sensors are only live in reverse and vice versa for the front ones?

[GiveMeABreak]

That isn't going to help! The parking assistance ECU does a self-check each time the vehicle is started. By disconnecting the sensors you have basically created more faults.

Try my touch test as you have referred to, but otherwise you need a decent diagnostic system like Lexia / Diagbox to determine which part of the system or which sensor is faulty.

Shorting them out is only going to destroy them.... but won't make the warning go away.

If you don't want the system working then it will need disabling with the diagnostic tools I mentioned above.

[gosnoid72]

Cheers Marc, I thought as much. I'll try the vibration test at the weekend.

[gosnoid72]

Lexia scan complete. Faulty sensor identified and changed. Parking system fixed!

[GiveMeABreak]

Great, thanks for the update.

When my C5 started playing up I changed one sensor, then a couple of weeks later the parking system fault message reappeared - but diagnostics confirmed a different sensor - changed and no problems. A month later it happened again - another sensor on a different location! So be aware that if you get this happening to you it may just be the end of service life of some of the sensors - so that's why it's important to check positions.

[gosnoid72]

I shall bear that in mind and glow in my small victory for a while! Thanks.