ABS - Audi A3 -1998 - Edinburgh andy
Hi All,

My mother had her Audi A3 -98 40k miles- in the garage to have the battery replaced - i thought 8 years was reasonable life for a battery ??any other thoughts on this would be welcome-.

Anyway when the battery was replaced and the car started the abs light came on and after diagnosis a faulty rear wheel abs sensor was replaced acouple of days later.

When starting up with the new rear wheel abs sensor the light came on again - another diagnosis and the other rear wheel sensor was fauly

my questiosn are thus:

is it possible the low battery voltage from a battery on the way out would stop the abs light from coming on??
this is what the garage said

Should both faulty abs sensors not have showed up on the diagnosis???

Is 180 a reasonable price??? thats for each one!! (100 labour 2hours, 50 odd sensor, & vat)

Is 8 years a reasonable expectation for an abs sensor??

What is the normal problems with abs sensors ??? -i thought it was a build up of dirt, and corrosion-

Car make/model added to subject header - DD
ABS - Audi A3 -1998 - Aprilia
Sounds very fishy.

Nothing to do with low battery.

Labour is way OTT - book time is 20 minutes to change a sensor - can't imagine where they got two hours from. These sensors generally last 10+ years. Could be a complete mis-diagnosis and there is nothing wrong with the sensors - could be some other fault with the ABS system. Sensors failing within days of each other would be like lightening striking twice.
ABS - Audi A3 -1998 - adverse camber
I have seen a low voltage cause abs light on - on an old porsche. not powering the pump enough to pressurise the system.

abs sensor changes are fairly quick and easy on an a3 - if you can get the sensor out - but that shouldnt be a problem if you dont mind it coming out broken.

did they use diagnostics to detect the fault ? or are they messing about ?

The abs controllers have a bad name. But Its dificult to understand how changing the battery could cause problems, unless they bashed the controller doing it ? But Both rear sensors going seems very odd.
ABS - Audi A3 -1998 - Edinburgh andy
Yes im told they had it on diagnostic machine ( each time), and this is how they found out it was a doggy sensor.

I was wondering if the points below could have contributed/ caused the fault??

When the battery was so low it was put on a charger- a trickle charger- not one of the high boost ones but the battery wasnt dosconnected could this have blown the abs Ecu???

about a week ago car went into to another garage to have prob with back braks sored - must have been an easy fix as no no charge but could tampering eg hammering etc have damaged the sensor and /or its electrical connections


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