Abs sensor reading double speed

CrispyEdd

CrispyEdd

Member
United-Kingdom
Having some issues with my abs.
I got the beeps and flashing light plus usual abs and traction yellows.

It clears on restart but comes back about 10 seconds driving later.

First vcds message was right Rear mechanical fail. So I removed the original sensor and replaced with non genuine (horrified I know). Anyway now I get a message saying implausible reading.

Vcds shows one sensor showing double speed all the time. Doesn't say with wheel on screen. Is it right Rear?

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Could this be the abs ring on the hub or the sensor?

Guess I could plug oem back in and see if it reads the same double speed.
 
Once it is plugged in either the sensor is not compatible or there is a voltage problem. Never experienced either with my A2.
 
I'll refit the original audi sensor and see if the error and reading are the same as the new sensor, that will indicate the abs ring or wires.
My gut says abs ring.

Can't find much of rear drum abs rings anyone know where there's a thread on them?
 
CrispyEdd said:
I'll refit the original audi sensor and see if the error and reading are the same as the new sensor, that will indicate the abs ring or wires.
My gut says abs ring.

Can't find much of rear drum abs rings anyone know where there's a thread on them?
Click to expand...
i thinks it's on the hub, with the wheel bearing
 
My experience with this problem is with a Merc that has a canbus system (very voltage sensitive) Swapping sensors left to right and attempting to follow the problem brought me back to the reluctor ring.
Not sure where that is on an A2 rear. On the front it is part of the wheel bearing. Very unusual failure and as far as I know requires a new bearing.
Perhaps it is the same on the rear? Never had problems there, I would swap around sensors and see if the problem moves.
 
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Has to be an incompatible sensor, merc sprinters are awesome if you fit a wrong or incorrect side sensor the vehicle knows and generates a superb fault code description
 
OK thanks for advice, I forgot the simple idea.of swapping sensors! Will see what codes the old sensor throws and what readings first. I will take a butchers at the other sensors bolts first before swapping, hopefully not as crusty as the bad ones was!
 
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CrispyEdd said:
I'll refit the original audi sensor and see if the error and reading are the same as the new sensor, that will indicate the abs ring or wires.
My gut says abs ring.

Can't find much of rear drum abs rings anyone know where there's a thread on them?
Click to expand...
compare ohms reading on new (not audi) and one of 3 good ones to see if there is a difference in value
 
CrispyEdd said:
Hi
What setting will I need to be on?
What's likely reading going to be for that test?
Click to expand...
Hello Edd,

Not sure what multimeter you have but check this short YouTube clip out to hopefully assist:


I don’t know what values you’re looking to observe but anything that’s wildly different between the factory sensor and the aftermarket should provide you enough evidence on where to get the next sensor from.

Kind regards,

Tom
 
Just to close this thread off, somewhat mixed feelings about it!
I couldn't get my multimeter probes to reach the two pins sadly as they Brereton two deep into the sensor!! Grrrrr even after trimming down..

Anyway I took the new sensor off thatbwas reading twice the speed.

I figured that if the speed reading is there then cables are okay and abs ring maybe okay.

I cleaned the old one and refit that with new stainless bolt. M10 16mm.

With vcds I reset the "implausible signal intermittent" code.

Upon test drive to see if original sensor was giving same.code, Lowe and behold nothing happened.
The car drove like normal no lights beeps or codes.

What the hell, that's classic A2 mischief.

So glad that it's fixed for now but I don't know what it was other than perhaps dirt...or maybe an A2 just wants constant
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attention 😅
 
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