C4 picasso rear speed sensor

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c4GPicasso
Donor 2021
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Joined: 08 Feb 2021, 18:15

C4 picasso rear speed sensor

Post by c4GPicasso »

Hi,

Im getting the Abs/ESR fault along with hill start, parking brake etc

Lexia scan gives me these fault codes C1391 00 & C0037 11.

My vin is VF7**************[VIN obfuscated, can be read by forum staff] Its a 2014 C4 Grand picasso (B78)

Lets say the abs sensor is faulty. What is the procedure? ie remove the Disc, parking brake motor, dust shield and then remove the sensor? will the fuel tank have to be dropped? ( I used to own a PUG 407 and this had to be done then) From a quick look the wiring from the sensor disappears under the heat shield at one end of the fuel tank.
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GiveMeABreak
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Re: C4 picasso rear speed sensor

Post by GiveMeABreak »

Ok, so C003711 refers to the rear left wheel speed sensor. There's a short circuit to earth.

When this fault is active, then it will deactivate a lot of ESP functionality, such as the ABS, ESP (including all traction control functions), Tyre pressure monitoring, Hill Start, Emergency Braking Assistance, Stop & Start system, and Semi-Automatic Parking if fitted). So that is why you will have all these errors.

Your suspect is the rear left wheel speed sensor of course, or the connections to and from it or the actual ESP ECU.

The other fault C139100 is a generic fault of the ESP ECU and that can be caused by the same speed sensor fault above. So I would focus on the rear left speed sensor first of all and once you've sorted that out, the other fault should also disappear. So just be aware of the deactivation of the said safety systems - as you'll have no ABS and no ESP.

As for replacing, I'll pop something up for your shortly...

Ok, so here's how to replace the rear wheel speed sensor:

Lift and support the vehicle.
C4GP A.PNG
C4GPB.PNG
Disconnect the connector (at "a").
Remove the bolt (1) of the rear wheel speed sensor.
Remove the rear wheel speed sensor (2).
When refitting, avoid impacts to the head of the rear wheel sensor.

Tightening Torque of the Rear Speed sensor bolt is 1 daNm

Then run another Global Test and clear the fault codes.

RichardW
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Re: C4 picasso rear speed sensor

Post by RichardW »

Given the propensity for these to rot the wires to the rear brake unit, I would check the wiring carefully before forking out for a new sensor although the sensors are same left / right, so it should be possible to swap them over and see if the fault moves which will point to either the sensor or wiring being at fault. Mind you,I'm willing to bet it won't be that easy to get out....

soni12
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Joined: 27 Feb 2021, 00:08

Re: C4 picasso rear speed sensor

Post by soni12 »

hi. I had the same problem... abs asr parking brake engine faults... Diagbox showed me many faults but i had rear right speed sensor fault as well. The car was driving very short distance for over 4 weeks, but from few days I driving for work about 40km one way.. and after 5 days the all faults gone.. And I think it could be problem with battery,, if the faults come back i let you know...