Hi all, 

I have recently put some slightly bigger wheels and tyres on my 8V, as I set off after fitting them It shows that I have a tyre pressure system fault, ESC fault, hill hold assist unavailable and start/stop fault. I had none of these show up before the new size wheels and tyres, any advice on how to fix this? 
 

thanks, Joe. 

We're the TPMS sensors transferred to the new wheels? 

Hello Joe,

Thanks for joining the forum and posting your plea. 
All the fault codes you show -and more - could (in caps) be associated with a below par battery, but it would be a bit of a coincidence that these should be displayed immediately after you have fitted different wheels sizes - and tyres. 

What size wheels and tyres were originally fitted? 
What size wheels and tyres are now fitted? 
Are the current wheel and tyre sizes listed as alternative fitment for your model, and if so, have you adjusted the tyre pressures to their recommended level? 
Kind regards,

Gareth.

Hi Gareth,

Looks like Joe didn't reply, but are you are suggesting that the 8V model's ECU will somehow detect that wheels and/or tyres of a different size have been fitted, even though the TPMS has been reset?

My brother in South Africa is thinking of fitting higher profile tyres to his 2014 A3 because his standard 225/45-17 tyres keep getting damaged on SA's pothole-ridden roads. (If you think the UK is bad, they're billiard table smooth compared to some of SA's secondary roads...). I suggested he fits 16" wheels & tyres. but he doesn't want the added expense of buying wheels. We know that higher profile 17" tyres will affect speedometer accuracy and may result in clearance / fouling issues, but didn't think the ECU may object too!

Kind regards, Chris

2 hours ago, ChrisMP said:

Hi Gareth,

Looks like Joe didn't reply, but are you are suggesting that the 8V model's ECU will somehow detect that wheels and/or tyres of a different size have been fitted, even though the TPMS has been reset?

My brother in South Africa is thinking of fitting higher profile tyres to his 2014 A3 because his standard 225/45-17 tyres keep getting damaged on SA's pothole-ridden roads. (If you think the UK is bad, they're billiard table smooth compared to some of SA's secondary roads...). I suggested he fits 16" wheels & tyres. but he doesn't want the added expense of buying wheels. We know that higher profile 17" tyres will affect speedometer accuracy and may result in clearance / fouling issues, but didn't think the ECU may object too!

Kind regards, Chris

 

Shouldn't be an issue as long as the rolling radius matches what came off , usually within 4% .  

Hi. The speed of the car is calculated using an average of the ABS sensors on each wheel. If the ECU is expecting a certain value for one wheel rotation and sees a different value to that for a bigger wheel, I’d say it would throw up an ESC fault. That would take in ABS fault, TPMS anti skid etc. You probably need to have a diagnostic on the car to program the ECU it for the new wheel size. 

1 hour ago, The Verb said:

Hi. The speed of the car is calculated using an average of the ABS sensors on each wheel. If the ECU is expecting a certain value for one wheel rotation and sees a different value to that for a bigger wheel, I’d say it would throw up an ESC fault. That would take in ABS fault, TPMS anti skid etc. You probably need to have a diagnostic on the car to program the ECU it for the new wheel size. 

Or fit the right sized  tyres to keep things correct. 👍. 

Wow, thanks for your very prompt and informative replies - much appreciated!

Best regards,

Chris