Abs Sensors

According to Citroen parts list the front ABS sensor for my car is 0271 04 454155
It is a Teves Ate type.

I have the chance of a sensor part number 484552 which looks identical and is listed for MK2 2.1 td. Is there any difference? and are they interchangeable?

Hi Jacky

The front and rear sensors have different cable lengths and grommets but the sensors and plugs are the same on the Teves system. The grommets are fixed to the cables but it is possible to modify and fit as Citroenxm reports doing this successfully. I suspect that the one currently on ebay is a rear one hence the different number. The reference in the adv to 2.1TD is a red herring, just the car type it was bought for and not a sensor specific to that car.

John

I needed to resolve the 'ABS not working' problem on my car for the MOT. Even though it was intermittent it was sure to fail at the wrong time.
Anyway, I couldn't lay my hands on one quick enough but read on here that the problem often lies within the cable rather than the sensor itself. I can't remember who wrote the post but I thought it was worth a try.

It was the front o/s sensor so I cut the cable about 6" from the sensor and the same from the plug end. I ran in a new piece of cable in between and soldered the joints. Sealed them with silicone and guess what........No more warning lights and all working great. Sailed through the MOT also. That was 3 weeks ago and the ABS is still working fine.

For vthose with the intermittent problem this must be worth a try.

Hi Jacky

Great, well done!

Thanks for the follow up on how you cleared the fault. It is a most valuable post as it confirms the suspicions of a number of us. As I recall both PeterN and CitroenXM have mentioned making repairs/modifications to sensor cables previously and now your report confirms this as a really viable fix. That you could revive an apparently dead sensor and did not need to disturb its setting are real bonuses. Worth adding to the self help files.

John

It was PeterN who I think first announced this fix for the sensors..

I also know that David Hallworth has succeded too on his S2 V6 24v...

Ive not done, or needed to do it with any of my 3 yet..

Rgds
Paul

This post has been edited by citroenxm on October 02, 2008 12:52 pm

It's the cable or a connector. Did you test the piece of cable you cut out afterwards? Measure impedance, flexed it while testing it? Would be interesting to know what you found. An intermittent fault is often just caused by a poor connection, unless a cable has been damaged by excessive bending or chafing.
I've written about my ABS blues with my former XM somewhere before. I obtained new front sensors under guarantee, but it was just a connector, so now I still have a nice set of spare sensors And I can tell you this was not the only time a poor connections caused intermittent electrical faults on Citroens I have owned. Surprisingly my current Cit is free from these gremlins

Rather then start a new topic for ABS, I thought Id add this here..

A stranage problem on the V6 12v ABS...

First startup, light check, light goes out... start off no problems!!

However, if I come to a stop, and slowly crawl with my foot on the brake, just as the car is about to stop Light comes on... HOWEVER, if I drive away and flick the ignition key into start position (being auto the starter does NOT activate) the electrics go out as they do if the starter was turning, the light will go out.. BUT ONLY if the car is moving forward when I do it... If the car is stopped when I do it, the light stays on... If I do it in reverse, the light stays on too...

Its only when I go forward and turn the key.... if I come to a stop again, light will come back on... and so on...

Is this a sensor fault? Over active or under active? Or is it an ECU problem??

I have upgraded the sensors to LATER Bendix Sensors with the fatter bodies.. but not sure if I have the correct MAIN ECU in the car..

Cheers guys!

Rgds
Paul

Hi Paul

The reason the light goes out when you turn the key to the start position is that it causes the abs system to restart the start up diagnostic routine, i had a real pita fault that would come up (sometimes) at very low speed as you describe which turned out to be the well known bad connection in the wheel arch (Bendix), hopefully your fault is just a sensor or bad connection, not sure that many ecu's die do they?

D

Hi Dean,
Yes I realise that, however, what is causeing it to put the light on at low speed? Sensor over acting or as you said, a bad connection, but why only at low speeds, almost stopping..??

Rgds
Paul

I have no idea Paul, it must be something to do with the speed at which the diagnostic takes place. If im honest i dont know, i have had the abs cutting in at very low speeds as you mention and effectivly turning the brakes off just as your about to stop but without triggering the light, then sometimes just as i start to move off the abs light come on but with the system working as it should
I think the only way to diagnose the problem apart from taking the usual resistence readings of each sensor is to have the fault codes read off the ecu, unless someone knows a cheat

Good luck with it,

D

My 2.0i car now has the ABS lamp on permanently, from the moment you turn the key to the moment you come to a halt. Is there anything I can test to see what's wrong?

When I switch on the ignition, the lamp flickers briefly at the point it would normally go out (about 1.5 - 2 secs later) but stays on.

Hi Thwarted

The fact that it flickers indicates that the ECU is getting a 12v power supply and is then failing the static self test routine. That is just a simple resistance check on the 4 ABS sensors and perhaps the ABS block printed circuit board. As Dean says go after the sensor resistance checks first at the main plug to the ABS ECU. For Bendix system you should find values close to either 1.2k ohms or 2.3k ohms (both types are permitted and may even be mixed). If you find higher resistance values then try again at the connector plugs (front wheel arch and top of rear subframe). I think the later positioning is a designers idea of a joke. Cleaning up the connectors may clear the fault. If a sensor is showing open circuit then check again at the connector by that wheel. This will tell you whether to look for a broken wire in the car loom or to replace that sensor. The sensor wire pair numbers are listed in the Bendix ABS self help item.

John

Much appreciated