Abs warning is this MOT checkpoint ?

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redzzed
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Abs warning is this MOT checkpoint ?

Post by redzzed »

Since i had my back brakes done , the Abs warning light is on on the dashboard panel .
The brakes are fine , not sure about Abs 'cos i have nt braked hard enough to test it .

is this an Mot fail point ?/

i can probably just remove the fuse .

xantia 1.9 td sx R reg .

thx

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Re: Abs warning is this MOT checkpoint ?

Post by SaabC5 »

Yes, its a fail. Pulling the fuse won't work because when the reg is put on VOSA it identifies the car has ABS and that the light comes on with the ignition and then goes off within 5 seconds of the car starting. If this doesn't happen its an automatic fail.
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Re: Abs warning is this MOT checkpoint ?

Post by citronut »

i do know if you pull the fuse ( No. 14 ) out for the ABS on a BX this will put the warning lamp on,

dont know if the same happens with the XANT
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Re: Abs warning is this MOT checkpoint ?

Post by Old-Guy »

The ABS warning light ON indicates that ABS is inactive. Basically the light is ON until the ABS ECU has powered up and successfully completed its self-test. It can't test the sensors until the car starts moving (it waits until the car is doing about 20 mph). The ECU continues to monitor the inputs from the sensors and will indicate a fault if the sensor inputs are apparently nonsensical. After the ECU has detected a fault, it won't turn the light off until the whole system including sensors has passed test. So when a problem has been 'fixed', a road test exceeding 20 mph is needed to clear the fault and get the ECU to turn the light OFF.

The usual causes of the ECU light are bad circuit connections and sensor failures.

Search the forum for threads on the subject for lots more information.
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Re: Abs warning is this MOT checkpoint ?

Post by Hell Razor5543 »

What was done on the back brakes, and by whom? If they were done by a garage I would be taking it back to them.
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Re: Abs warning is this MOT checkpoint ?

Post by citroenxm »

Old-Guy wrote:The ABS warning light ON indicates that ABS is inactive. Basically the light is ON until the ABS ECU has powered up and successfully completed its self-test. It can't test the sensors until the car starts moving (it waits until the car is doing about 20 mph). The ECU continues to monitor the inputs from the sensors and will indicate a fault if the sensor inputs are apparently nonsensical. After the ECU has detected a fault, it won't turn the light off until the whole system including sensors has passed test. So when a problem has been 'fixed', a road test exceeding 20 mph is needed to clear the fault and get the ECU to turn the light OFF.

The usual causes of the ECU light are bad circuit connections and sensor failures.

Search the forum for threads on the subject for lots more information.
Thats only applies if you have had a new sensor replaced or such. And not if you have simply changed disks and pads..

Once that has gone through the test stage and all os ok it should do the light flicker and out after five seconds .. untill such thatca sensor packs in, a relay or more rarely the ecu itself has packed it.
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Re: Abs warning is this MOT checkpoint ?

Post by redzzed »

Thx for replies , the back brakes were done by a trusted indi and i think it was disc and pad..cant remember because
i went off to usa for 6 weeks right after .
Will find the bill .
i took facia fuse 6 out but it made no difference to the warning light .
It goes in for mot tomorrow morning .
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Re: Abs warning is this MOT checkpoint ?

Post by Hell Razor5543 »

It is VERY likely to fail the MoT. Some things are advisory (such as the side airbag system), others are not (such as the ABS and main airbag system).

When the electronics in a car power up, they run a basic set of start-up tests (not unlike a PC, when it is turned on). The assumption is that, until they pass back a 'test passed' message, the electronics are assumed to be faulty, and the car flags this up. When the tests come back OK the relevant lights are put out. Pulling the fuse for the ABS ECU means that it cannot power up or run its tests, so it must be faulty.
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Re: Abs warning is this MOT checkpoint ?

Post by redzzed »

It failed the Mot on that (abs) and front number plate.
Car is booked in on thursday at place that did the brakes
fingers crossed .
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Re: Abs warning is this MOT checkpoint ?

Post by CitroJim »

Fingers crossed but the ABS fault must be fixed for a pass. Pulling the fuse will make no difference to the warning light as it's fail-safe. Taking the blub out won't help either as the MOT man is looking for a flash sequence whist the ABS ECU goes through its self-test.

As James says, no light or a light behaving badly is assumed to be a duff ABS and therefore a fail.
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Re: Abs warning is this MOT checkpoint ?

Post by redzzed »

All sorted , took the car back to the indi who did the rear brakes , but it turned out to be the ns front sensor , he replaced that
..whole job (for abs) cost £127 . Took car back for free retest and it sailed thru .not bad for a 17 year old car i suppose .

thx for all the comments .
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Re: Abs warning is this MOT checkpoint ?

Post by Hell Razor5543 »

redzzed wrote:All sorted , took the car back to the indi who did the rear brakes , but it turned out to be the ns front sensor , he replaced that
..whole job (for abs) cost £127 . Took car back for free retest and it sailed thru .not bad for a 17 year old car i suppose .

thx for all the comments .
Ouch! New sensors for Gracie cost me less than £60 the front pair, although I fitted them myself.
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Re: Abs warning is this MOT checkpoint ?

Post by citroenxm »

Mk.1 and mk.2 sensors are quite different.. and with quite a different price too..

thats not a bad price for a mk.1 sensor with fitting to me..
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