2016 C4 Picasso Abs, esp, parking brake and tyre inflation monitor faults showing

[RichardW]

The ABS unit on these is buried in the bulkhead on the driver's side. What faults have you got? If it's a rear one, it's most likely to be the wiring at the rear rubbed through.

[merlin667]

I need to dig this topic up: my C4 GP has also these troubles, but i did not had time to make the diagnostic today. In the past I had twice or three times an error with the parking brake (Shortcut to Ground if i remember correctly during driving) but just the ACC was disabled. Nothing more happened and after restarting it went away.
Today my wife called me lots of errors are popping up. I checked shortly, all errors are related to the ABS / ESP Module.
Made a short test drive: ABS isnt working at all. if i switch it of and back on 1 or 2 out of 10 the ABS is working and the messages are not appearing.
If i sum up with the history of the errors of the parking brake, which is currently working fine and (hopefully) with an error of an rear ABS sensor i should dig into the connector at the back seats or am i missing something?

[RichardW]

Welcome!

Ideally it needs to be scanned to see where the fault it - but on these the wires rubbing through at the rear is very common, and easy to check. Take the wheels off and open up the loom and check it for any suspect spots.

[merlin667]

I will check later with diagbox for my correct error codes. but as i've seen these issues (wiring at the fender and the connection below the seats) are quite common i just wanted to confirm i'm going into the right direction and not missing something really important. Today its raining, so for my opinion its even more related to bad wiring.

[merlin667]

Hi, i just wanted to give a short update: checked with diagnostics, right rear ABS sensor was mentioned with short to ground. repaired the wiringing at the rear axle inside the corrugated tubing. I dont think the wiring or the insulation is wrong, because i grabed a twisted wire pair out of an cable which is supposed to be used for moving application (cable chain) and they have the same flexibility.
But for my opinion the issue is that there is no additional cover outside of the wiring pair (like fleece tape or outter plastic layer). What i also noticed is that the problematic section of the wiring was at the fixing positions, where the outer tube is vibrating like the rear axle. As result of this i protected the wires with the fleece tape normally used (like at the end where the ABS and EPB wires are splitting up) and hopefully i does not happen again.

[Byngo9]

Yes, mine was in the same place as well. Unrelated but I also found a broken wire in the passenger side mirror ( blind spot hadn't been working for a while) so fixed that too whilst the soldering iron, heat gun and heatshrink was at hand.

[Justmee]

Here you go:

7825 is the rear right Wheel Sensor.
7800 is the ESP ECU

7032 is the Right Hand Rear Wheel Speed Signal Reference on Pin 1 going to Pin 37 of the ECU via the harness interconnections.
7031 Right Hand Rear Wheel Speed Signal on Pin 2 going to pin 22 of the ECU via the harness interconnections.

These go back to the ESP ECU via the 80 AR SP main harness and the ICK5D interconnection.

Main Wiring Diagram



Close up of Rear Right Wheel Sensor



Wiring Harness 80 AR SP



The wheel sensor wiring then connects with ICK5D under the rear seats as shown:



Here is the 4 pin ICK5D connector showing the wheel speed sensor pins in the interconnection: It should be a black 4 pin connector (not 6 pin as shown on the diagram - but can't be sure - you know the French!)

Looks like this poste will help with my problem but I cant see two of the pictures ie the ick5d location

What needs to come out to get to that plug?
re this thread viewtopic.php?t=85677

[Byngo9]

I believe ick5d is under the main rear seats, under the carpet below the central seat. I have fixed my abs wiring twice now on the drivers side rear ( 2 separate breaks on the same wire but several inches apart). I had thoughts of maybe running a new twisted pair from ick5d to the sensor but didn't fancy the trauma in the end. We will see how long the 2nd splice lasts.

[Justmee]

I believe ick5d is under the main rear seats, under the carpet below the central seat. I have fixed my abs wiring twice now on the drivers side rear ( 2 separate breaks on the same wire but several inches apart). I had thoughts of maybe running a new twisted pair from ick5d to the sensor but didn't fancy the trauma in the end. We will see how long the 2nd splice lasts.

It's actually not that hard once you know where it is. Stiff cable will feed to where you want to go. Large grommet you can make a tight hole in. If you check out my post linked above it shows you.

[Byngo9]

Ok, great that you took those pics. You went a few steps further than me, but then my broken wires were easier to find. I will definitely take lessons from your post if the same happens again.
Thanks.