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Discussion Starter #1
Has anybody tried replacing an ABS sensor? Does it require any special equipment to tell the management computer to recognize the new sensor?

I have been getting an intermittent stabilitrak warning light at quite low speed left hand bends. Several garages have failed to find a problem and I wanted to try swapping the sensors from one side to the other myself to see if the problem switched to right hand bends and prove that a sensor needs replacing. It looks quite easy to do, but I don't to do it and fine the computer does not recognize the sensor.

Thanks,
Richard.
 

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Are the tyres on the same axel the same ?
I had this after a puncture when one odd one went on. Now changed to the same as the others. it may well be the diameter catching the ABS out.
 

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Traction control cutting in on slow left handers is a known issue - I had it early on in ownership. The likely culprit is tyres and / or tracking. As Spiny said, relative diameters (ie tread wear) between sides or front to rear is the first thing to check.
 

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Yup, same problem started on mine after I had new tyres which I put on the rear. I took advice here that it's a known problem because new tyres are slightly larger ( = less worn). Seemed unlikely to me but I'm no mechanic and I trust people's advice here with respect to Amperas, often more than I'd trust a garage (even Bellingers!!)

It's in for a service soon and I may ask then to swap back to front to see if it makes a difference.
 

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Has anybody tried replacing an ABS sensor? Does it require any special equipment to tell the management computer to recognize the new sensor?

I have been getting an intermittent stabilitrak warning light at quite low speed left hand bends. Several garages have failed to find a problem and I wanted to try swapping the sensors from one side to the other myself to see if the problem switched to right hand bends and prove that a sensor needs replacing. It looks quite easy to do, but I don't to do it and fine the computer does not recognize the sensor.

Thanks,
Richard.
Don't do anything to your sensors, they are working fine.

The system is hypersensitive to tyre size differences.

Swap you rear tyres for your front tyres and the problem will go away. The issue is that your fronts are significantly [i.e. significant enough that the system detects this] more worn than you rears.

Go check, and tell me I am right!!! :p:D

I'll bet you £100 that if you do that swap today, and the tyre pressures are correct, you will no longer be able to reproduce the effect.

There are several threads about this here, now, under different titles and assumptions about the problem. But this is it. Tyre rolling radius.
 

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Discussion Starter #6
I have already had them swapped front to back and tried slightly higher pressures (41 psi) and slightly lower pressures (36) all round, but I still get the light. They are Michelins at one end and budgets at the other so maybe it's that, but they appear to be the same diameter when I tried measuring them. There's a lot of wear left in them so I'm a bit reluctant to replace them just to see if fixes the light. I'm currently running with the budgets at the front so they wear out first and then I'll replace them to have Michelins all round. It is bit annoying though as I have to adapt my driving style for left hand bends to prevent the loss of power kicking in all the time.
 

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I ended up changing all four recently on my MY13. Two still had plenty of tread but I was advised they were perishing. I guess made back in 2012 or even earlier so just age?
 

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At today's 3y service they advised me the tread on fronts and backs, and I had the newer fronts switched to the back (so now fronts are 8mm and rears are 6mm).

They asked why I wanted them changed so I explained about the theory above. He didn't think it would make any difference but I promised to let him know the outcome.

Which I will know once I go towards he M3, where there is a bend on which I can reproduce the problem almost at will. I'll try to get out there tomorrow or following day.
 

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Today I have been to my "test bend". It's a long left hander. and twice I can recall the cruise control being knocked off by the traction control engaging, at about 60 - not really pushing it that much. I don't go that way much and I often wouldn't be going that quick, so there is nothing truly accurate about this test.
However, having had the tyres swapped back last week, so that the newer ones are now on the front and the originals are on the back, I could not make the traction control flicker, on either of two passes.

So I'm going with Donald's theory, that having larger diameter tyres (albeit only by dint of them being newer) on the back DOES cause the traction control to kick in on left handers at some speed. As mentioned about the tread was measured by Bellingers as 2mm different front to back.

I just really wish I'd thought to go to the corner before having the tyres swapped back to front so that I could be even more convincing.
 

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Discussion Starter #12
Tried swapping them side to side as well now, at both ends, but it's not made any difference. The light still comes on and power is cut on left hand bends two or three times every journey, even when I'm taking it easy.
 

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Can you post photos of each tyre with a depth gauge? I am just wondering if you have some weird mix of tyres where the layout is left-right deepest at the front and right-left deepest at the back.
 

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1.5mm difference is enough to trigger this, but with different makes on it is difficult to advise.

I would have the 5mm tyres on the front and the lowest tread of the other two on the rear left to try to avoid this.

TBH I would chuck the low tread tyres, that really is not a lot of tread? If the 5mm ones are the budgets personally I'd just take a new set of GY efficient grips and sell the cheap ones or store them for a rainy day. It's very annoying to get a puncture in the last flush of a set of matching tyres, I'd keep them just for puncture survival purposes.
 

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Just had the old girl a few days and noticed exactly the same fault.
I used to be a mechanic up until 5 yrs ago and wouldn’t have thought a few mil would have done this.
It’s got different wheels on it and the tyres are new but I guess I’m going to find the original wheels and new tyres.
Thanks for helping everyone out with these posts.
 
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