abs light flicker and sensors test update

pete@co.uk · Post by **pete@co.uk** » 10 Jul 2005, 04:48

hi guys
im bringing this topic up agian for a very good reason becouse the abs has just started to work agian of its own accord so whats happening now is that when i turn the ign on the light flickers then goes out another time it,ll stay on so if i switch the ign on and off it will eventully stay off and remain off so do you think guys this is a problem with the abs ecu itself or just sensors or connections
your thoughts guys
pete..............................

jeremy · Post by **jeremy** » 10 Jul 2005, 13:27

Xantia ECU's are know to give problems - have a look at
http://www.bba-reman.com/index.htm
and
http://www.carelect.demon.co.uk/
If you've got a faulty sensor the thing cannot work properly. Its possible that a break in the sleeving has connected again and may sometimes work but it must be dealt with. i ended up having to listen to each sensor with an audio amp till I found the one with the problem.
jeremy

Stempy · Post by **Stempy** » 10 Jul 2005, 14:13

I had a similar thing with my first Xantia which turned out to be a dodgy wheel sensor. The light would come on at random but eventually it stayed on all the time so I was able to trace it.

pete@co.uk · Post by **pete@co.uk** » 10 Jul 2005, 15:09

hi and thanks guys
the only sensor that came up duff when tested them before was the o/s/r one so i could,nt understand it suddenly starting to work the other thing i don,t understand is why its started to work after ive been fiddleing about under the dash repiaring the the heater blower as if there,s a lose connection under there and why does turning the ign off and on bring the abs into action very puzzleing.
any idea,s guys
pete.......................

Stempy · Post by **Stempy** » 11 Jul 2005, 02:42

If the sensor is a bit dodgy it might pass the initial test when you switch the ignition on at standstill, but if its output is failing then the ecu will not be getting sufficient pulses as you drive, so it will trigger the fault light.

pete@co.uk · Post by **pete@co.uk** » 11 Jul 2005, 03:06

hi stempy
thanks for that ok well the light has been staying off even when driving ive had the car about a month now and its been on since ive had the car it now just this week its decided to stay off for some reason anyway the mot,s due soon so ive got to find out whats wrong before the mot but i don,t want to waste money changing sensors when it could be somthing else the osr sensor got an 0 reading when i checked it a few weeks ago so it came as surprise when the light went out this week and if i turn ign off and on the light goes out stays out but in saying that its decided to stay on agian today so whats going on ill change the sensor no problem but what if that doesnt cure it ive wasted my money and still have the same fault. I know ive had it before on another car changed the sensor then so that was ok then straght away the other rear wheel sensor went faulty it was,nt showing the fault till i changed the first one so you see im a bit wary. but that was on a rover 620
pete............

jeremy · Post by **jeremy** » 11 Jul 2005, 03:21

You measured the resistance of all 4 sensors and found one was open circuited.
The system requires all 4 sensors to be good before it will work.
Unless you are very clumsy replacing 1 sensor cannot damage another.
If the cables have rotted or frayed internally due to flexing it is likely that those on an axle will fail at about the same time as they have been subjected to the same use.
It is likely that you have an ECU problem as well if the light has gone out with the faulty sensor still on the vehicle.
Jeremy

ghostrider · Post by **ghostrider** » 11 Jul 2005, 03:36

Could be that there is an intermittent fault on that sensor that read 0, do you really mean 0 which mans that there is a dead short in that sensor?
As the co ax corroding seems to be a problem with some cars it could be that it has shorted to the centre core, the idea of simply cutting the cable back until you find continuity and attaching new cable from that point seems like a good one to me
pete
________
Hemp marijuana

pete@co.uk · Post by **pete@co.uk** » 11 Jul 2005, 03:53

thanks guys
ok well ill replace the sensor and see what happens but i will test the old one when its off and if i can repair it i will.
pete.........................................

jeremy · Post by **jeremy** » 11 Jul 2005, 03:59

Good point Ghost. Meters take a bit of working out for resistance readings - especially digitals.(I always have to short it and read to remember what I'm looking for!) Pete may be worth re-metering odd one - then compare with shorted meter probes.
jeremy

pete@co.uk · Post by **pete@co.uk** » 11 Jul 2005, 05:14

thanks jeremy
ill give that a try tommorow and see what i get
pete..........................

pete@co.uk · Post by **pete@co.uk** » 12 Jul 2005, 00:12

hi guys and thanks for your help
ok ive tried the test agian and the odd sensor comes up with 1 wich is the same as having the probes apart if i shorten the probes the meter reads 0.01 so it looks like i have a broken circut in that sensor o/s/r all the other sensors are the same as before.
any ideas guys
pete............................

jeremy · Post by **jeremy** » 12 Jul 2005, 01:19

Yes Its probably the cable - but definitely that sensor. You may have other problems as well like ECU but they will all have to be worked through.
The only official repair for the sensor is replacement.
Jeremy

pete@co.uk · Post by **pete@co.uk** » 13 Jul 2005, 04:57

hi jeremy
well im going to replace that sensor its probably the cable like you said but i hope there,s nothing wrong with the ecu
pete.........................

jeremy · Post by **jeremy** » 13 Jul 2005, 05:08

I hope its not the ECU but those fitted to mid 90's Xantias do fail quite frequently. They are repairable by specialists - I think I've already posted 2 links.
Jeremy