Tyre light, losing my mind slowly

[OneFrenchEgg]

So. About four years ago my tyre light (it doesn't identify an individual tyre) kept coming on. I had the sensors replaced at a local garage, all good. Then a couple of months ago, it started again - eventually permanently on. I thought I'd identified the tyre that was always showing as low.

In that time:

Tyre valve replaced - the garage checked the tyre, replaced the valve. Light on as soon as I picked it up.

Checked at different garage, they inflated it, said all ok. I insisted this was not ok, that the light would come on again if I picked it up with nothing changed - they replaced two tyres as worn (including the one I thought was an issue). This is the garage that I always use and which did the sensors last time.

Tyre light on once a week at least. Same problem tyre I think. I check the pressure at home, it always shows as low.

What is going on?

Wheels can become porous or corrosion/gunk can stop the bead sealing correctly. If the pressure is actually low when you check it and it’s not the tyre or valve causing it then it must be the wheel. Any decent tyre place will wire brush the bead seating area and if that fails then pick up a wheel from eBay, should be cheap.

Wow thank you, sounds like there are a couple of options to try. I'll ask about taking the tyre off and cleaning the wheel, and also resetting the software (cheaper options to start with!)

Is an alloy a wheel?
So I checked yesterday - I always fill all the tyres to the right pressure at the same time, so
Front passenger
Rear driver

Both are the ones I suspected and both had lost pressure. One did look corroded (bubbly) on the wheel front, but not one that had lost pressure.

So it's the wheels I suspect.

Is an alloy a wheel?

Yes it is. It just refers to what they're made of - shorthand for "alloy wheel".

Thank you - I wasn't sure if it was part of it! I think replacement wheels are about £600 new. Yikes.

I had pretty much the same series of events and it turns out the wheel was cracked. It had about 5 trips to tyre people who were underneath the ruddy thing and changes of valves before I actually asked if that could be the issue and it was. I had thought it might be something that would be visible but clearly not. That wasn’t cheap….

Just to add, the joy of the light not being on anymore can’t be underestimated.

OP, I wondered about the software. Did the garage who changed the tyres reset the reference pressures? (my car is a ford and it's one of the dashboard menu options). My local independent garage never resets the reference after changing a tyre, so normally a week or so later the tyre light comes on.
What I do is just pump all the tyres to the recommended values in the manual (my car also has them on a sticker in the drivers door frame), then do the reset on the menu.
If the light goes again after that, then you can be more certain that you are actually losing air.

Yes! It's so horrible when it comes on.

I can do ' checking the tyre pressure' via the stalks on the steering wheel? Makes no difference, light goes off and then back again a few days later. I'm thinking it's the wheels.

I've got a VW T Roc and had this with mine after a new tyre was fitted. Turns out that they hadn't reset the software in the car? I had to get the manual out of the glove box and go through the tyre pressure reset then it was fine. I nearly took it to the dealer it was annoying me so much. On mine, there's a CAR button on the central display, and you reset through that?

It was the ominous ‘bong’ that used to get on my nerves.

@OneFrenchEgg I had the same with one of mine a few months ago. Turned out I had a crack in the alloy wheel. Cost £100 to have the wheel repaired. Depending on how damaged it is it won't necessarily need the wheel replacing.

You have a slow puncture?

I just don't see why neither garage looked for this, instead of just the tyres or valves, I kept telling them.

Mine didn't look until I had the tyre changed because it was going bald. Got up the next day and the tyre had lost all its air overnight so I rang them and got them to take it back in so at that point they were looking for a fault with the wheel because it couldn't have been the tyre. I think the assumption is just that it's a tyre issue until it becomes obvious that it can't be.

No it was just a little backstreet place and I don’t think they had the tech to do it properly - happened twice and each time I had just had a tyre replaced , since it was reset this week it has remained off thankfully so £20 well spent , I was getting concerned as if I had an actual tyre issue I would just dismiss it as alert was already on

It’s the wheel not the tyre?

So as an update, I have :

Had someone change a balance (£20), picked it up with light still on

Had someone else change the rear tyres - light came on a week later

Had someone diagnose faulty valves, a 'main dealer' job

Had someone else look at it, inflate the tyres, find no punctures, reset the software (I have said I expect to see them in a week or two) but not check the wheels themselves.

I am getting to the sell the car and be done with it phase 😫

Aaaargh.
Had two valve stems changed, no light for two weeks.
Light reappeared. Went on holiday.
Came back, inflated tyres, light now permanent. Minor loss of air in tyres, not as bad. Light won't go.
I just want to torch the bloody car. Any journey now is beyond stressful.