Xantia 1.9td VSX 96 with ABS problem

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big_lorry
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Xantia 1.9td VSX 96 with ABS problem

Post by big_lorry »

Hi all
Superb forum, hope someone can help.
My ABS warning light is on, handbook say's abs is disabled due to potential problem.
Back street garage told me the computer showed no fault and the light was off, it sometimes goes off but not for long.
Does the advice of a dirty censor sound right and if so is it an easy task to put right.
P.S. currently have suspension problem hence browsing forum hope it's not linked as I thought I would try sort the ABS first.
Cheers
arry_b
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Post by arry_b »

Sounds like a sensor / wiring problem.
Golden rule of electronics repair: Start with the cheapest thing first!
Clean the sensors, the toothed wheels and the sensors. Then disconnect, clean and reconnect *all* the wiring to the sensors and the ABS unit, examine all the wiring for dodgy looking insulation and chafing. Finally, if you've got the radio code, disconnect the battery and leave it a few hours to reset the ECUs.
There's an 80% chance that'll fix things. Hope you're in that percentage.
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AndersDK
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Post by AndersDK »

ABS problems would not be linked to any suspension problems.
Most likely Arry's advice will cure the ABS problems.
About suspension you have to be more specific on detailed symptoms to receive our bets [;)]
Merry Xmas [^]
David Goddard
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Post by David Goddard »

Strange. The ECU stores fault codes until cleared. Certainly sensor faults (low output, etc.) are stored. The ECU is smart. Say the ECU detects a low output from a sensor, it won't put the light on straight away. It will come on, and stay on, the next time you start the car. Drive for say 1/2 mile, then stop and start the engine - the light may well go out. This is typical of a sensor giving a low output. Some steel across a sensor pole pieces, pole piece bent due to stome damage or a dirty connector.
There is one component which isn't monitored by the ECU - the ABS relay. This is the green relay in the main fuse box in front of the ABS unit. Usually reliable but maybe one of the contacts is dirty? This is one of the components which directly powers the ABS light.
big_lorry
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Post by big_lorry »

Cheers Guys
I'll give this a try and let you know how I get on.
I will also come back soon with more info on my suspension issue.
Merry Xmas
wheeler
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Post by wheeler »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by David Goddard</i>

Strange. The ECU stores fault codes until cleared.
There is one component which isn't monitored by the ECU - the ABS relay. This is the green relay in the main fuse box in front of the ABS unit.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
i cant say for sure about the ABS ECU but if ECUs detect a fault once and it doesent ocurr again after a certain amount of self tests (aproxx 30 times) it will clear the fault from its memory,this may explain why there was no fault codes in it.
Again i cant say for sure about the xantia but on the XM (mk2) the green ABS relay IS monitored by the ECU & can register fault codes,just thought it may have been the same on the xantia.
jeremy
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Post by jeremy »

sounds like an intermittent sensor fault. Try metering all sensors and see if there are similar readings for resistance.
If one has a broken wire (I had 3 on my BX) it may show but may not if the wire contacts at rest and only breaks the circuit when the suspension moves and causes the wire to flex. This is more fun to check and in the absence of an oscilloscope I connected each sensor in turn to an audio amplifier and drove round listening to each sensor in turn until I heard what sounded like very slight sparking. This proved to be a broken screen on the cable.
Jeremy
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