Hi all,

Ive had a bit of a search around and found no existing topic that covers my query.

For a couple of weeks, my ESP & ABS lights have been illuminated permanently. This started as soon as i had the two front tyres for some higher profile ones.

Ive plugged the VAG COM cable in and it shows an ABS speed sensor fault on both the front wheels.

With the timing of the fault and the unlikliness that both sensors would fail at the same time i am thinking that the car believing the front and rear wheels are doing two different speeds due to rolling radius may be whats triggering the error.

Anyone know if thats correct?

Having checked on a calculator, the front wheels are now showing a 6.9% increase on the speed of the rear wheels.

Regards

Phill

I'm not sure anyone will be able to answer this for the glaringly obvious reason ... who on earth would fit tyres with a different profile on the front and rear? Even stretched rubber fans stick with the same profile. Also what your calculator probably didn't allow for is the % of wear on the rear's making the true figure greater than 6.9%.

I have 215/45/16 on the front and 205/45/16 on the rear with no problems at all. That’s only 10mm difference though.

I wouldnt normally consider changing the profiles without doing all four, however the fronts were wearing thin, it was a bit snowy outside and i had a pair of winter tyres kicking around....as with so many things in life, it seemed a good idea at the time :-D

Edited 14 March, 201214 yr by theflipt

Same here, had them lying around. Fronts were low so decided to change them

What size did you fit to the front then?

Hi sam - i presently have 205/45/16 on the rear with 205/55/16 on the front.

I appreciate its far from ideal, but its only a temporary change before replacing all four tyres over easter.

Just wanted to know if this could be the reason for the fault so i dont spend lots finding other reasons for it.

Cheers all

Phill

Does it come on straight away? As soon as you start driving or

does it come on after say... 10 minutes?

"Just wanted to know if this could be the reason for the fault so i dont spend lots finding other reasons for it."

Yes, that's the reason. ABS systems don't like different diameter tyres/wheels but it will not harm the system or the car, other than ABS/ASR non-functioning.

When you get the tyres all the same, you'll be able to reset the fault with no issues.

Just hope you don't have a crash until you can get normal tyre sizes put back on, as your insurance won't be valid.

Had this on a firms Transit. It only hapened above 60MPH, but a Ford bloke couldn't find it ,although his laptop did indicate one wheel was showing problems.

Turned out that one tyre was smaler than the other three. Strangely enough ,a Kwik fit manager spotted problem straight away.( But then he'd be in my book, one of the good guys)

I had a similar problem when I replaced my front wheels with ones off a shopping trolley, the car wouldn't steer until I put a proper set of wheels back on

Seriously, as previously stated, your insurance will be invalid unless you have notified them, I notified my insurance company I was putting on skoda permissable winter tyres on and they wanted to bump up my premium just for them.

When you get the tyres all the same, you'll be able to reset the fault with no issues.

I have had a similar issue but not because of tyre size, I think I may have a flat spot on a non OEM bearing I fitted a few months back. So once I have replaced it will I need to reset the fault? If so, how?

Width isn't the issue here, fitting different widths on some cars is standard (rwd cars sometimes have larger rears to handle the power and smaller fronts for quicker steering), my post referred to the profile or height of the tyre, this is the problem and as pointed out in the event of an accident any assessor will flag it up to the insurance company who won't invalidate any claim against you (they can't) but could seek to recover the cost from you, you also run the risk they wouldn't pay out on anything you claimed for. It's also why your car has the ESP/ABS issue and why it wouldn't pass an MOT in its current state.

Grr666, it comes on pretty much as soon as you hit a steady speed, so usually within 30 secs.

On note of the fault itself, having larger circumference wheels on the front than the back would light up the esp/abs lights, and changing them to the standard should make the ecu happy again?

Me being an idiot is a much cheaper option than anything else to fix, so i would prefer that :-)

On note of the fault itself, having larger circumference wheels on the front than the back would light up the esp/abs lights, and changing them to the standard should make the ecu happy again?

Putting standard sizes back on the front will make it work again.

It's throwing up a fault as ABS and TCS work based on the rotational speed of each wheel. One wheel going faster than the rest, it's lost grip so TCS cuts the power. One wheel stopped and the rest going round, it's locked up so ABS kicks in.

Your ABS and TCS aren't working as the front wheels are constantly rotating at a different speed to the rear.

Unless you want to reprogram your ECU to tell it that the front wheels will permanently be going x% slower than the rears (probably not even possible) then the cheapest option is to fit the correct tyre size

Grr666, it comes on pretty much as soon as you hit a steady speed, so usually within 30 secs.

On note of the fault itself, having larger circumference wheels on the front than the back would light up the esp/abs lights, and changing them to the standard should make the ecu happy again?

Me being an idiot is a much cheaper option than anything else to fix, so i would prefer that :-)

READ MY post on what happened to a Transit with one tyre smaller than others. The smaler tyres are revolving faster than the bigger ones. Sensors take this as a fault, and shut down ABS. At a certain spped the difference kiks out an error, and ABS shuts down . You need all tyres to be same size.

Cheers for the assistance guys

I have a 2010 AUDI A4 B8 2.0TFSI and I recently had a flat front tyre. My front tyres were already low so I decided to replace both. After I replaced them, I got Park brake, ABS, ESP and Engine light on my dashboard.

 

I checked codes at the garage. I had 2 wheel speed sensors, park brake, ABS, and a couple of other errors (see below). I've heard sometimes a weak alternator can cause this kind of thing but before I replaced it I found people talking about having different size tires can cause issues. 

 

Error codes i had after tire replacement:

- 00285
- 00283
- 00473
- 00955
- 01330
- J540

 

I checked and found the front tires they replaced on my car were lower profile to my rear tires (40 vs 45). I drove the car for 15 minutes that day. When I got home I turned the car off and on again, all lights had gone except for the engine light. I'm going to get my tires replaced with correct matching profiles (45/45) and then clear codes and see how I go. 

 

I'll update once I've done it to let you know how it went. 

 

If that fails, I might need to replace alternator. 

 

Thanks for people's previous replies. 

You won't need an alternator, just the right size tyres fitted will fix it.

You should probably change who you buy your tyres from, inability to read a two digit number is indicative of a single digit IQ.

1 hour ago, sepulchrave said:

You won't need an alternator, just the right size tyres fitted will fix it.

You should probably change who you buy your tyres from, inability to read a two digit number is indicative of a single digit IQ.

 

Yes. They're swapping for free. Hopefully thats the end of it. Will still need to clear the codes though. 

 

On 14/03/2012 at 22:38, luke90_vrs said:

I have 215/45/16 on the front and 205/45/16 on the rear with no problems at all. That’s only 10mm difference though.

That's a difference in tyre width, not tyre height/profile. 

On 16/03/2020 at 14:35, bigd09audi said:

I have a 2010 AUDI A4 B8 2.0TFSI and I recently had a flat front tyre. My front tyres were already low so I decided to replace both. After I replaced them, I got Park brake, ABS, ESP and Engine light on my dashboard.

 

I checked codes at the garage. I had 2 wheel speed sensors, park brake, ABS, and a couple of other errors (see below). I've heard sometimes a weak alternator can cause this kind of thing but before I replaced it I found people talking about having different size tires can cause issues. 

 

Error codes i had after tire replacement:

- 00285
- 00283
- 00473
- 00955
- 01330
- J540

 

I checked and found the front tires they replaced on my car were lower profile to my rear tires (40 vs 45). I drove the car for 15 minutes that day. When I got home I turned the car off and on again, all lights had gone except for the engine light. I'm going to get my tires replaced with correct matching profiles (45/45) and then clear codes and see how I go. 

 

I'll update once I've done it to let you know how it went. 

 

If that fails, I might need to replace alternator. 

 

Thanks for people's previous replies. 

 

In the end, swapped tyres over to standard (245/45/17) all round. Drove for 10 minutes. Turn car off/on, all lights cleared on dashboard and no limp home mode. 

 

Lesson learned, different profile tyres can mess with you wheel speed sensors which messes with your speedometer, ABS, ESP.... 

 

That's what I gathered anyway. 

 

 

5 hours ago, bigd09audi said:

That's a difference in tyre width, not tyre height/profile. 

As the profile is a percentage of the width, not an actual measurement, rolling diameter is still affected.

That's why profile usually decreases as width increases on a given vehicle, to keep the overall diameter approx the same.

Different rolling diameter as a result of underinflated tyres will trigger the ASR light, ask me how I know...