Electrican help please? Citroen C4GP ABS wiring mare (fixed)

[pauldoubleyou]

Hi everyone, I have a Citroen C4 grand picasso 1.8 petrol, and it has a permanent fault with the ABS system I cant clear.

I have a full Lexia and am getting a ground to positive / negative / open circuit on the drivers front ABS sensor. I have replaced it twice, and also cut out the plug inside the wing to rule it out.

I am now leaning towards there being a wiriing fault between the ABS unit under the passenger wing and the sensor.

So - two options. Does anyone have a pinout of the ABS ECU plug? Then i could just replace the entire wire from the plug.. or ill have to trace it through the loom which i would like to avoid. I cant seem to find a wiring diagram to save my life.

Thanks in advance for any replies!

[RichardW]

Paul

If you can post up the RP of the car I will see if I can get a wiring diag out for it.

[pauldoubleyou]

Hi thanks for the reply, I believe it is one of the codes below?


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[Hell Razor5543]

The RP code is 11217FV, and shows that your car started life on 26 July 2007, in the Vigo (Spain) factory. I got this information from the RP calculator site;

http://www.citroen-ds-id.com/gen/Gen_Organr.html

[RichardW]

OK, I'll try and have a look later and see what I can find.

[pauldoubleyou]

Thanks buddy

[RichardW]

It looks like the wires go through the big bundle at the back of the battery which is a known weak point for water getting in and rotting wires.

7815 is the OSF sensor.

[pauldoubleyou]

You sir are an absolute star, i hadnt scrolled all the way down and was going to reply with a key for the sensors!

Superb. Ill have a look and see what i can see, i think the wire goes round the back of the block, behind the battery and then into the passenger arch and the ABS / ESP ecu (which shows as 7800 and thats in the arch according to your picture and mine ive attached).



Just got to locate pins 18 and 6 and run new wires, i thin this will be tidier than pulling the loom apart. As ive snipped the plug, this equates to:

Sensor----- Black(Pin1,7012U)------------------------Pin18 ABS ECU(7800)
Sensor -----White(Pin2,7011U)-----------------------Pin6 ABS ECU(7800)

Very very big thanks for the help

[pauldoubleyou]

As a pet hate, i never like finding threads through google etc with no conclusion.

I ran a new wire from the ABS plug to the sensor, soldered it up and it has since cleared the issue. Obviously must have been a break in the wiring in the loom. only problems I encountered was that a few of the sensors have the same wiring colour at the ABS plug, but oddly the only ones that were blue/pink twisted were for this sensor. At the ABS plug (at the back of the module behind the front left wheel arch liner) you cant actually see what wires go into the plug - so i had to drill a small hole into the top to identify the correct wires for pins 6 and 18.

Needless to say it has cleared the ABS, ESC and Handbrake errors.

[GiveMeABreak]

Thanks for the update - always good to get the conclusion and I'm pleased you have it fixed now.

[pauldoubleyou]

One thing that was interesting is that the fault wouldnt clear itself without being binned off Lexia. Also, there is a right and wrong way to wire in an ABS sensor, I know there is two wires but they need to be the right way round for it to register.

It seems like the car firstly does a sensor check, confirms they are all there, then secondly does its coherence checks. Another sensor failed coherence once I started driving away but it was due to a split CV boot and grease on the sensor.

[Nemesis84]

Apologies for reviving an old thread but this is my EXACT issue - except rear right abs sensor wire (yellow) has a break on it somewhere! I'd like to test by running external wire to create new circuit to abs sensor but don't know what pin on the abs ecu connector it should go to! Does anyone still have the pin wiring diagram mentioned in the thread? Also is it really true it needs lexia to delete the error codes? I can't pay the garage £100 for 30 seconds work! :S

[GiveMeABreak]

Hi and welcome.

I'll need a VIN in order to access the correct wiring diagram, then I can advise you of the pinouts. Post or PM it.

[Nemesis84]

Hi and welcome.

I'll need a VIN in order to access the correct wiring diagram, then I can advise you of the pinouts. Post or PM it.

Thanks - I've sent a PM

[Nemesis84]

Then again - it's sat in outbox not sent... not sure why! Here's what it said!

Many thanks for your offer of help! My Vin is VF7**************[VIN obfuscated, can be read by forum staff]***************

I have got a circuit from right rear sensor pin 2 (tan?) to the one in the arrow here - but not sure where pin 1 yellow should go - or if the wire is even still yellow by the time it gets to the head connector! Can these connectors be opened?

https://photos.app.goo.gl/LSAMcAYvG4HBRGMS7