C5 Mk 1 ABS Light

[hawkeye]

Hi chaps,

The ABS light, after showing intermittently for a few weeks, has now come on permanently, accompanied by the usual "ABS Fault" display. Does anyone have details of the pin-outs for the ABS ECU connector so that I can find out which one of the wheel sensors is at fault? There's a sticky with Xantia details but I can't find one for the C5.

Thanks,

Peter

[XantiAl]

Hello Peter, Wish I could offer some help, just gone down with the same problem & dismayed and surprised to see very little on here in the way of comment or previous issues.
I turned to utube for anything that could be found, mostly Americana it seems.
The wheel sensors are the obvious starting point, using a multi meter, mine all seem to read the same ohms. I havnt however been able to get a voltage while spinning the wheel, there should be a voltage apparently.
Do you have the option of finding a member with a Lexia? it should I believe locate which wheel if a sensor is at fault.

I dont know where to go from here frankly,very exasperating this problem, I know what Id like to do, just turn it off and motor on without it,not feasable it seems.
Do let me know if you get sorted.
cheers , Alan ,W Cornwall

[RichardW]

Lexia...will point you at exactly what it's upset about.

[hawkeye]

Interim report, chaps,

Thanks to Andy F's Lexia the fault has been identified as "Rear axle electrovalve". BoL is no help in identifying this but, apart from the height corrector electrovalve I can't recall another similar item on the rear axle. Does the height corrector e/v sound as though it might be the culprit? Presumably it sends some sort of load-sensing/levelling signal to the ABS ECU to bias the brake effort front to rear - any help/ideas/useful comments gratefully accepted!

Peter

[Andy F]

Hi Peter,

Nice to meet you at the weekend.

Any luck finding out about the brake electro valve? I have had a look around the internet and cant find any mention of a rear electrovalve causing a braking fault. Am I right in thinking the suspension and braking system are completely independent?

Andy

[RichardW]

I rather suspect that is the electrovalve inside the ABS block that controls the supply pressure to the rear brakes. Doubt it's going to be cheap - think new ABS block required....

Edit: New one from Citroen only comes with ABS ECU and costs £1120..... Should be possible to fit a used part though I'd have thought. Might be worth seeing if bba-reman can repair them?

[hawkeye]

Hi chaps,

Problem now solved - Richard hit the nail on the head by identifying the electrovalves in the ABS ECU. I got a remanufactured unit (with a lifetime guarantee for the ECU) from BBA Reman (who were very helpful). It cost £340 (inc VAT and postage) but the brake system is now fully operable. It wasn't too difficult to replace the unit, and in fact it took longer to sort out the battery tray bolts that sheered off as soon as I put a spanner on them. As well as a sorted brake system I was also able to adjust the throttle cable to compensate for stretch and eradicate the family of arachnids that had taken up residence under the battery tray. Thanks to all those that have offered help and advice.

Peter

[Hell Razor5543]

Next time you have to do any work on seized bolts you might want to treat them to a daily does of Plus Gas for a week prior to the work. This usually frees them off.