Tyre pressure loss indicator

Dean Shirt

Registered User
Hi again folks, I’m going to bore you to death again. Had my 2017 A4 avant for around 2/3 weeks now. Since ownership I have had the tyre pressure loss indicator pop up twice now for my rear right tyre. First time I just topped it up and reset, second time I was a little suspicious of a puncture. Today it’s come on again so I know something isn’t right and it is losing air. Can I just ask at what percentage does it need to lose air to make the warning light come on the dash?

In my previous post I stated that the owner before me had different size wheels put on the front without knowing. 245/40/18 on the rear and bigger 245/45/18 on the front. Could this potentially cause the light to trigger?

Also I’m assuming a puncture could be fixed dependant on where the puncture is located?
Thanks in advance
 

RAF_S7

Well-Known Member
Gold Supporter
Punctures can be fixed, but it depends on where the actual puncture point is on the tire. Could also be the valve leaking.

Different tire sizes won’t matter, as when you reset the TMPS via MMI, it calibrates the system to the rolling diameter of each corner.

Not sure about the % drop in pressure needed to trigger the warning, but if it triggers, you’ve lost air which shouldn’t be happening.

:racer:
 

Dean Shirt

Registered User
Punctures can be fixed, but it depends on where the actual puncture point is on the tire. Could also be the valve leaking.

Different tire sizes won’t matter, as when you reset the TMPS via MMI, it calibrates the system to the rolling diameter of each corner.

Not sure about the % drop in pressure needed to trigger the warning, but if it triggers, you’ve lost air which shouldn’t be happening.

:racer:
Cheers for the comment, can leaking valves be changed?
 

RAF_S7

Well-Known Member
Gold Supporter

jds_sg

Registered User
Can I just ask at what percentage does it need to lose air to make the warning light come on the dash?

I had this come up once on my previous A4 which had 18" wheels. The right rear triggered the indicator and it had lost about 7-8 psi from 37psi so about 20%ish I think.
 

Dean Shirt

Registered User
UPDATE- after looking at my tyre myself this morning I have found a screw, can this be repaired
EA42496C-DB0A-4204-AFBD-AC65943786C7.jpeg
 

Spearo

Registered User
Yeah it could be repaired -it looks like the screw is more or less in middle of the tyre, but if it was me, I’d be replacing that tyre and any like it because of the cracked and degraded rubber , and actually it doesn’t look like you have much tread depth left anyway so those tyres are due for replacement
 

Dean Shirt

Registered User
I do agree and more than likely may replace. This car was only just MOT’D and they didn’t mention this plus it’s had 2 inspections? Would they check this
 

Spearo

Registered User
You would like to think So wouldn’t you - makes you wonder how thoroughly they look at things !
An Audi inspection is worth nothing in my book - just an excuse to get some more money and try and flog you some new gear - surprised they didn’t try and sell you new rubber !
 

L_G

Registered User
How do you find out which tyre the system thinks is affected?
 

L_G

Registered User
Thanks, I don't recall reading that but maybe I missed it!

For some reason I only seem to get the initial warning on starting the car up
 

Dean Shirt

Registered User
Thanks, I don't recall reading that but maybe I missed it!

For some reason I only seem to get the initial warning on starting the car up
Mine came on mid journey the other night, but then every time I switch the car on I get the message as well.
 
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