ABS warning light - Permanent Fault Wheel Sensor Signal fix

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My Name: C3CAR

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Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 140000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
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Engine name: DV4 16-valve diesel (90 PS)
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ABS warning light appears on the dashboard. First time it came with a warning gong, subsequent times there was no sound. The light can be reset with by switching the ignition off. With the ignition on, the warning light appears without moving a wheel and after about 5 to 10 seconds.

ABS warning light on Citroen C3
ABS warning light on Citroen C3

Lexia code says:

Permanent fault
Front LH wheel speed sensor signal Open circuit, short circuit to positive, short circuit to earth

Lexia ABS warning error Citroen C3
Lexia ABS warning error Citroen C3


A suggestion for this fault is to remove the offending sensor and clean the magnetic track. It is also worth cleaning the sensor. There was more dirt on the sensor than the track for this C3.


To remove the sensor and clean the magnetic track, remove the 13mm rusted bolt, and keep the broken washer (it is still has one). Lever up, carefully, without breaking the plastic, the whole sensor from its housing. You can see it partially lifted in the picture. Getting started is the hardest part.


Citroen C3 ABS wheel sensor removal
Citroen C3 ABS wheel sensor removal

With the sensor removed, it can be cleaned with a cloth. A small brush or rolled up cloth and be poked into the hole. With the brush or cloth in place, rotate the brake disc to simulate wheel rotation and clean the magnetic track.

Refitting the sensor is much easier than removal, but it is still tight in its housing, tap it back into place.


While I was there, I loosened the inner arch near the side repeater to access the ABS Sensor plug to meter it. 1666 ohms seems ok, and put it back together.


The fault didn't come back with the ignition, stayed off for a run and more importantly, stayed off for the MOT tester 8-)
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My Name: C3CAR

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Posts: 2634
Joined: Wed May 04, 2011 10:01 am
Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 140000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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Thinking back, which may or not be relevant. The ABS fault light came on very soon after, say, within 200m of a very heavy braking episode that gave the amazon driver a fright. No contact was made, no exchange of details, just a friendly wave.

Live data showed the 4 wheels matching the vehicle speed which made me reluctant to blame the wheel sensor but the clean did the trick.
My Name: Neilcmusic1

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Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.6
Fuel Type: Petrol
Mileage: 80000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
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Great guide, did this in 1/2 hour, two tips, first of all bolt cant be taken out with a normal spanner as it's sunk, I used a dog bone spanner or of course you can use a socket, second tip the sensor was as stated fixed in tight so I put a screwdriver in where the bolt was and twisted it loose, it is plastic so be careful but there isn't a thread in it the sensor it's in the main body so you won't damage the thread,

Great guide, I did think that I should have a new sensor on standby but the amount of spare parts I have in my house that I've bought "just in case" and never used is beyond a joke.
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My Name: Ozvtr

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Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
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DPF: No
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Neilcmusic1 wrote: Wed Feb 16, 2022 5:17 pm the amount of spare parts I have in my house that I've bought "just in case" and never used is beyond a joke.
As a professional and amateur technician, I can tell you: "If you have a spare...that part will never break". Better than auto insurance! :lol:
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