ABS not working on 1 wheel

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M7R
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ABS not working on 1 wheel

Post by M7R »

Friends polo has an odd one, the ABS light seems to randomly come one but clears if the car is turned off and back on, and last time I checked it didn’t store a fault.

However when I have tried the brakes, if braking hard enough for ABS it locks the front left, and the pedal sinks. You can feel the other wheels cycling and it basically keeps going until the car has come to stop even if you let back off the brake.

We have changed one of the ABs sensors as one was playing up but I can’t remember which it was, she seems to think it was the left front but I’m not 100% sure.

Anyone else come across this? I’m tempted to just chuck another couple of sensors on the front for the cost of them and make sure the ABS ring is clean on both front wheels,

The car seems to drive fine and doesn’t pull under braking,
dipstr
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Re: ABS not working on 1 wheel

Post by dipstr »

I would check for any codes first.cheapest option would be to change sensors first but be warned the absence unit is very common for failing. Usually gives a warning light just cannot for the life of me remember which wheel it says is faulty.

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dipstr
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Re: ABS not working on 1 wheel

Post by dipstr »

Abs unit soz

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M7R
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Re: ABS not working on 1 wheel

Post by M7R »

I’ll have a scan tomorrow, hopefully it’s not the unit as seems to work on the other wheels. May try bleeding it all again too just encase it’s that.
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937carrera
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Re: ABS not working on 1 wheel

Post by 937carrera »

You're on the right lines.

I would wait for the ABS light to come on again and then read the code to find out exactly which wheel is the issue.

If you changed the front left, perhaps that sensor is new faulty.

Cleaning the ring and bleeding won't do any harm, but that probably isn't your problem
M7R
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Re: ABS not working on 1 wheel

Post by M7R »

Well I think it’s the module that’s playing up.

Scanned it a little while ago and it had an implausible signal code. Can’t remember which but..

Tried to bleed the front brake it was clear. Then tried to bleed it via VCDs which has a bleed setting. And the pedal goes odd...it doesn’t seem to feel right when the abs activates.

Then used the VCDS test sequence and with your foot on the brake it activates the ABS on one wheel at a time.. other 3 the pedal stays hard and you can feel it pulsing.
Left hand front as soon as the ABS activates the pedal dives to the floor. This is wheels stationary.

Then both front wheels jacked up, ignition on (vcds not connected) and if you rotate the left front wheel the ABS activates but the wheel spins..

Try the same on the right and the ABs kicks in like traction control and stops the wheel dead!

So now thinking it’s not the pump but the control module under it that’s toast on the front left?
dipstr
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Re: ABS not working on 1 wheel

Post by dipstr »

Sounds about right mate. Seem to remember there was a thread about it and am sure that it had a fix

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M7R
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Re: ABS not working on 1 wheel

Post by M7R »

Okay so i need to try some cleaver searching then, at least I’m barking up the right tree, I rather like the little pocket rocket so I’m determined to get it back spot on!
dipstr
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Re: ABS not working on 1 wheel

Post by dipstr »

Am sure the tread is on here you will just have to search for it

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M7R
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Re: ABS not working on 1 wheel

Post by M7R »

Yeah sorry that’s what I meant
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