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C4 - DS4 Owners :: Forums :: C4 Towing :: C4 Towing, roof bars, bicycle carriers and roof boxes

2015 C4GP: tow bar electronics woes

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Mon Sep 28 2015, 11:53pm
Member No: #4763
Joined: Aug 03 2008
Location: australia
Got a 2015 GP and had the dealer install a towbar and factory towbar electrics. Being in Australia the first challenge was the 13-pin plug: we don't have that one here so I had to get a 13-pin to 7-pin converter, the one with a diode in there to make sure the rear lights both work.

That bit worked - trailer lights now all function. Now the problems. I was told that the 13-pin connector has a switch in there that senses something connected and if it does sense that it disables the rear parking sensors, disables the rear fog lights and activates the TSP program.

With just the connector attached and switched into reverse the car starts screaming at me - indicating the rear parking sensors tell me I'm very close to an obstacle. Of course there is nothing there and the screaming stops after 30 seconds or so being replaced with a message "parking assist system defective, a SERVICE light and the parking sensors being disabled.

I also checked the fog lights - they are still on regardless of anything being connected to the 13-pin.

I was wondering if anyone recognizes the symptoms - my dealer is at a loss and suggest I will "have to live with it"...


Tue Sep 29 2015, 01:56am

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
I have moved your post into the dedicated Towing forum.

There is a microswitch in the connector that tells the car when a connector is fitted.

Sounds like the adapter your using isn't tripping that micro switch.
Sat Oct 17 2015, 12:56am
Member No: #4763
Joined: Aug 03 2008
Location: australia
Or maybe the towbar electronic wasn't activated in the computer?

Anyone know how the car reacts when inserting a trailer plug without proper activation in the computer?

Wed Jan 06 2016, 02:51pm
Member No: #42824
Joined: Nov 29 2015
Location: Cardiff
I had a towbar and electrics fitted and the computer wasn't activated for the caravan. The car rear fog lamps worked as if that caravan wasn't there and the rear fog lamps on the caravan didn't work. The same for the reversing lamps. Had it recoded and all was well, until I had to have all the software re-installed, due to the eco stop start having never worked.

Then I had to have the caravan electrics coded again, but all is working as it should now.

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