Faulty ABS Sensor - Unable to set Steering Angle Sensor

[rossm]

Bit of a long-shot (and long-winded) technical question, hopefully someone can help, or this eventually helps someone with the same issue. So...

ABS, ESP and TPM lights all come on a couple of weeks ago. Codes were read and pointed to a faulty ABS Wheel Speed Sensor (Rear Left).

My vRS has 72k miles on it now and I understand this is fairly common. So, had planned to replace the hub (with integrated sensor) in the next week or so, which should clear the ABS fault.

BUT...in the meantime, I managed to run my battery flat...don't ask!!

After charging it back up, car started okay, but had an amber PAS warning light on the dash. Started driving, power steering was definitely active, but when making a sharp turn in either direction, the wheel seemed reluctant to self-centre (usually it'll slide through my hands, but now I was having to pull it back to centre).

Got a VCDS hooked up, which gave the following:

"00778 - Steering Angle Sensor (G85)"

So, followed the Ross-Tech wiki article on doing the Basic Setting for the Steering Angle Sensor.

Unfortunately, it's made things worse...now I've no power steering at all and also getting the following new fault code:

"02546 - Steering Limit Stop

005 - No or Incorrect Basic Setting / Adaptation"

I've tried and re-tried the process multiple times, ensuring to do the Steering Limit Stop Adaption each time, but no joy.

After hours of Googling, I found lots of forum posts reporting the same issue, but no answers. Eventually found something on an Audi forum that suggesting that when an ABS fault light is on, setting the Steering Angle Sensor is not possible. They had the same issue and after replacing the rear hub, the power-steering kicked back in as soon they went for a test drive.

I can't see why this would be the case, but just wanted to throw it out there, has anyone heard of or seen this before?

Might look at replacing the hub sooner rather than later now and will report back with what I find.

Cheers

Ross

[07 vRS Taxi]

I can see how the two systems are connected, the ABS modulator or ECU collects data from the steering angle sensor and relevant wheel speed sensors to determine if the vehicle is in over or understeer milliseconds before ESP is activated. It's not unusual for multiple parts of a system to fail when only one part is defective, id change the wheel speed sensor (if that's what you believe is at fault) then take it from there.

Sent from my LT26i using Tapatalk 2

[Aspman]

Speed sensor isn't part of the hub btw. There is a magnetic ring in the hub that rusts and damages the sensor when it expands. So you need to replace the hub and the sensor. Mine is going in for the same thing next week, same wheel too.

[07 vRS Taxi]

Speed sensor isn't part of the hub btw. There is a magnetic ring in the hub that rusts and damages the sensor when it expands. So you need to replace the hub and the sensor. Mine is going in for the same thing next week, same wheel too.

That is correct for almost every make and model, but the reason I never advise people on here which parts to change is parts should be tested, which usually requires the correct equipment, knowledge and workshop data. There are few qualified people on here so my best advice is often 'take it to a garage'

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[rossm]

the ABS modulator or ECU collects data from the steering angle sensor and relevant wheel speed sensors to determine if the vehicle is in over or understeer milliseconds before ESP is activated. It's not unusual for multiple parts of a system to fail when only one part is defective

Thanks, that makes makes sense why the systems are connected, if it'd been a malfunctioning steering angle sensor, I see why ESP would turn itself off. Still, I don't see the logic in ABS failure causing steering assist to shut down (or go in a state where basic setting for the angle sensor can't be achieved). Perhaps some clever over-ride that sets the steering angle to zero degrees constantly, whenever an ABS fault is detected. Would make sense, since VCDS didn't detect any change in the steering angle when I moved the wheel - was stuck at zero.

Speed sensor isn't part of the hub btw. There is a magnetic ring in the hub that rusts and damages the sensor when it expands. So you need to replace the hub and the sensor. Mine is going in for the same thing next week, same wheel too.

Good shout! I'm hearing the rusty ring is usually the cause (and I had heard some grinding after long journeys), hadn't forseen it might have damaged the speed sensor though. I'll get a sensor too. Hopefully can compare the resistance between left and right. If not, will just replace it to be safe.

Good luck with yours - and try to avoid getting a flat battery before it's fixed!!

[rossm]

Quick update on the power steering issue - after two days of fighting with the steering wheel, it miraculously cured itself mid-parking manoeuvre! PAS light is off and steering wheel self-centres again after cornering. Utterly bizarre!

Hoping to get the ABS problem sorted out tomorrow, so back to a clean bill of health.

[rossm]

All sorted! ABS fault was the hub right enough, the magnetic ring was rusty and deteriorated - photo below if it's of interest.

Couldn't find a way to test the sensor, but apart from some slight scoring on its surface it was visually okay so didn't replace it. Fault cleared after a test drive.

Power steering issue still unexplained, but given it a right good test today - all faults cleared and stayed off, that's us back to a clean bill of health!

Edited 14 April, 2013 by rossm

[Aby]

Strange, I came across a person who had the same fault. He took the car to Skoda Service because ABS light was on. They diagonised it as faulty wheel speed sensor rear right. But when they replaced the sensor the power steering light turned yellow. The owner was advised by the company that the light would go off during the course of driving but the problem got worse and he lost the power assist abd the light turned red. Towed the car back to service and was advised that the steering rack sensor was faulty. Replaced the rack and the steering came back on, the expensive for the new rack,was huge.

[j0hn]

Reviving an old thread but I am having exactly the same issue at the moment. I pulled the battery to be able to remove the steering wheel and replace the wiper switch. I have had a failed sensor and/or pickup ring (or knackered wiring) for some time and can't reset the steering angle or stop limit either. I also managed to melt a spark plug through a 20 minute idle while trying to run VCDS adaptions (I was running BKR8EIX plugs and I think it all got a bit hot).

Waiting for my laptop to charge up but I'm half tempted to just run the car around and see if the problem miraculously cures itself like the OP's did.