Tyre pressure warning

[ukgroucho]

Heading off on a 100 mile drive this morning and after about 4 or 5 miles I had a tyre pressure warning show up. Pretty unspecific in that it just said to check all the tyres and reset the MMI threshold value.

Pulled into a nearby layby and had a quick wander around and 'kicked the tyres' but nothing obvious.
Found a petrol station and paid the ripoff fee to use the pump - TWICE cos the hose was not long enough to reach around the car and do all 4 wheels from where the pump was tucked away in a corner and by the time I had turned the car around my 50p had expired - end of rant

Anyway all 4 tyres took a bit of air but nothing seemed seriously out of shape. I'm wondering if this is just a case of cool weather... My tyres would have been originally filled in July when it was 28 - 30C, I have to confess to not having checked them since ... new car complacency.

Anyone else seen this happen?

Anyone know if the tyre pressure sensor singles out an errant wheel if just one is 'down'? The alert I had just said to check all 4 wheels...

[Guest 2]

The C7 uses the in-direct system which just uses pulses from the abs sensor rather than specific valves in the tyres.

This system isn't smart enough to see which wheel it is hence the 4 wheel message. I enabled it on my a3 and works the best but due to doing 600 miles a week I check mine pretty regularly.

[ukgroucho]

Thanks Chris... I'll check 'em again tomorrow and just make sure I don't have a slow puncture, would not be the first time.

[retired99]

Before a recent trip I changed the tyre pressures to reflect a car with 4 passengers and their luggage.

Before the change front 2.2 bar rear 2.0 bar, after front 2.4 bar rear 2.6 bar. Quite a large change. I forget to reset the pressure monitoring system.

About 100 miles into the journey the car decided to show a warning. Clearly not a very sensitive system, although I suspect it would do a perfectly good job of telling you that one tyre had a significantly lower pressure than the others and stop you from running a really flat tyre.

[Hammer2001]

One day over the summer whilst on holiday in Cornwall I had the tyre pressure warning come up whilst travelling at 70mph on a dual carriageway.
The car was handling fine and I thought it may have been a false alarm. So I carried onto where I was going, but at reduced speed just incase.
When I had parked up, visually the tyres all looked fine, so I checked the tyre pressures and one of the rear tyres was a few psi lower that it should be.
Fortunately they had been pumped up to the full load pressures, so were still above the minimum recommended pressures.
I pumped the tyre back up, and carried on with the day. When I came back to the car, I checked the tyre before I set off.
Again it looked visually ok, but it had lost a few psi over about 5-6 hours. On closer inspection of the tyre, I spotted a small nail head, which had caused a slow puncture.
Luckily there was a Kwik fit, just around the corner, and I was able to get it repaired.

So I was glad I the car had this system, otherwise I wouldn't have spotted this puncture so quickly, which could have led to a more serious situation.

[Zaf]

I had a similar issue over the summer, visiting my folks up north and on the motorway i got a low tyre pressure warning on the front left. Car was driving fine so slowed down and continued to destination. Checked the tyre there and there was a screw in the tyre causing a slow puncture. Luckily Audi Blackburn was round the corner, took it in there and they repaired it free of charge.

[ukgroucho]

Well I just checked the tyres again and they were all a little low (1 to 1.5 PSI) but were consistent - both fronts the same, both rears the same - so I put the variance down to differences between the garage pressure gauge / pump and my digital gauge at home. I elected to top up to values measure on my home gauge - 32 PSI front and 30 rear - and will use that as my yardstick for additional checks over the next few days. I'm really surprised how low the front tyre pressure is on this vehicle, pretty sure my old C6 A6 ran 35 PSI.

Overall I think the pressure warning was just down to cooler weather, tyres that were set up by Audi at 28 or 30C and were being driven at 12C.

[Passatier3]

Before a recent trip I changed the tyre pressures to reflect a car with 4 passengers and their luggage.

Before the change front 2.2 bar rear 2.0 bar, after front 2.4 bar rear 2.6 bar. Quite a large change. I forget to reset the pressure monitoring system.

About 100 miles into the journey the car decided to show a warning. Clearly not a very sensitive system, although I suspect it would do a perfectly good job of telling you that one tyre had a significantly lower pressure than the others and stop you from running a really flat tyre.

Similar for me. Didn't know about resetting the pressure monitoring system as hadn't had the car long and had missed it when reading the handbook. Increased tyre pressures to collect son from uni with all his belongings and got a warning the next day!

Reset system, thanks to help on here, and no problems since.