Tyre Pressure Warning Light

[G-Hal]

Hi everyone,

I own a 71 plate Aygo which I bought in August 2023.

No problems with the car whatsoever (a massive improvement on my very old and knackered car) until the 14th of January 2024 when I had a puncture after getting a nail in my rear near side tyre.
The spare was put on by roadside assistance, it was then taken to the Toyota dealership to get a new tyre. 

Since then the tyre pressure warning light will repeatedly come on.

I check the tyre pressure every single time it happens and they are always well within the tolerance level usually they’re down to 33/34 at the front and 31/32 at the back. 
The recommended pressure for the front tyres is 35 psi and the rear is 33 psi. 

It was taken back to Toyota on the 24th of February, thinking I had a slow puncture somewhere, but they inspected it and said they couldn’t find a single thing wrong with the tyres. 
 

Since then, it’s happened on a number of occasions and it’s happened 4 times since Thursday last week so I decided enough was enough and have booked it back in for a full day to have it inspected. 
Still, every time it happens, I check the tyre pressures and they’re always fine. 
Visually, the tyres look fine, I’ve ran my hands over the tyres both outside and inside and can’t feel anything iffy. 
 

I believe that if the sensor is faulty it will flash, it doesn’t flash in my car, it comes on and stays on until I reset it when I do the tyre pressures. 
 

I was wondering if anyone could shed any light on what could be causing this as this warning never appeared at all until I had a new tyre fitted after that puncture in January. 
 

Thank you 🙂 

[Cyker]

IIRC the Aygo doesn't use TPMS sensors, and detects punctures by sensing if one wheel isn't turning at the same rate as the others.

It may just be there's a reset procedure that needs to be done (Check the manual), or there is some damage to one of the ABS wheel speed sensors which is causing this intermittently.

In my experience Toyota dealers tend not to be very good at diagnostics; You may be better off finding an experienced local garage or mechanic with a good reputation to look at it.

 

Edit: One stupid thing to check is the wheels are all the same size - Check the tyre sidewalls for something that looks like 175/55r15 or something like that, and make sure they're the same on all the tyres. It's unlikely but possible the wrong sized tyre was put on!

 

[Bper]

Hi Gayle.since you've already booked your Aygo for a full inspection, you can definitely highlight these possibilities to the dealership. Explain that it's an indirect system.Ask them to check the owner's manual or relevant resources for the proper reset procedure specific to your Aygo.

Mention the possibility of a faulty ABS wheel speed sensor causing the issue and request them to inspect the sensors for any damage.Ask them to confirm they have done this on your invoice

[G-Hal]

1 hour ago, Cyker said:

IIRC the Aygo doesn't use TPMS sensors, and detects punctures by sensing if one wheel isn't turning at the same rate as the others.

It may just be there's a reset procedure that needs to be done (Check the manual), or there is some damage to one of the ABS wheel speed sensors which is causing this intermittently.

In my experience Toyota dealers tend not to be very good at diagnostics; You may be better off finding an experienced local garage or mechanic with a good reputation to look at it.

 

Edit: One stupid thing to check is the wheels are all the same size - Check the tyre sidewalls for something that looks like 175/55r15 or something like that, and make sure they're the same on all the tyres. It's unlikely but possible the wrong sized tyre was put on!

 

I didn’t even think about making sure the tyres are the same ones! 
I’ll check that in the morning when I go to work. 
 

If I take it anywhere other than the dealership, it invalidates my warranty 🙄

It’s surely no coincidence this has only happened since the new tyre was put on. 
 

Thank you for taking the time to reply, I do appreciate it 🙂 

[G-Hal]

1 hour ago, Bper said:

Hi Gayle.since you've already booked your Aygo for a full inspection, you can definitely highlight these possibilities to the dealership. Explain that it's an indirect system.Ask them to check the owner's manual or relevant resources for the proper reset procedure specific to your Aygo.

Mention the possibility of a faulty ABS wheel speed sensor causing the issue and request them to inspect the sensors for any damage.Ask them to confirm they have done this on your invoice

Hiya,

I’m not going to be a pillock with them but I’m not going to accept “there’s nothing wrong with the car” because warning lights come on for a reason, whether that be a sensor fault or something actually wrong with the tyres. 
I’m no mechanic admittedly but there’s surely something up with it for the light to come on as much as it does.

Thing is, the car drives fine and when I check the pressures they’re always fine but I just know if I don’t check the pressures, it’ll bother me and the law of sod, the one time I don’t check them will be the one time I should! 

On a side note, if there was a slow puncture I’d know about it by now would you reckon? 
 

Thank you for this, I’ll definitely mention all of that - it’ll make me look like I know what I’m talking about 😉

I appreciate the reply 🙂 

[Cyker]

39 minutes ago, G-Hal said:

If I take it anywhere other than the dealership, it invalidates my warranty 🙄

Is this what they told you?

It is literally against the law for them to invalidate the warranty just because you took the car somewhere else, as long as they're VAT-registered and use the right parts and materials.

They definitely couldn't invalidate the warranty just from you getting someone else to look at the car.

 

One other thing I was wondering, is if the other tyres are quite old and thus worn - If so, the new one will be slightly bigger as it'll have more tread, but I don't know how sensitive the passive TPMS system is and whether it would notice that...

[G-Hal]

49 minutes ago, Cyker said:

Is this what they told you?

It is literally against the law for them to invalidate the warranty just because you took the car somewhere else, as long as they're VAT-registered and use the right parts and materials.

They definitely couldn't invalidate the warranty just from you getting someone else to look at the car.

 

One other thing I was wondering, is if the other tyres are quite old and thus worn - If so, the new one will be slightly bigger as it'll have more tread, but I don't know how sensitive the passive TPMS system is and whether it would notice that...

Yeah that’s what they said, that if anyone else other than a Toyota dealership does any work on the car at all then the warranty is completely void!

The chancers…

I’ve only ever owned cars that were proper second hand, sometimes third hand and were “sold as seen” so to speak.
This is the first newish car I’ve owned that comes with a proper warranty. 

The new tyre was a completely brand new one so that’s interesting because the other tyres will need replacing just before the MOT in November so yeah…that’s very helpful! 
 

All this advice is really helpful because it gives me something to go in with, thank you! 

[Wiz201]

It always needs a reset every time you do anything with the tyres, even if you just increase the pressure in them a little.

[G-Hal]

40 minutes ago, Wiz201 said:

It always needs a reset every time you do anything with the tyres, even if you just increase the pressure in them a little.

But for the warning light to come on with alarming regularity, when there’s nothing wrong with the tyres or the pressure, isn’t normal.

That warning light never appeared a single time in 5 months of owning the car until I had to get a new wheel after a puncture in January. 

[FROSTYBALLS]

What you haven't said is whether you have reset the system. The owners manual refers to resetting the system as initialisation - and there is a description of how to do this in the owners manual. The initialisation button is located inside the glovebox.

Tbe system does need initialising after changing a tyre, tyre pressures, etc.

 

[G-Hal]

11 hours ago, FROSTYBALLS said:

What you haven't said is whether you have reset the system. The owners manual refers to resetting the system as initialisation - and there is a description of how to do this in the owners manual. The initialisation button is located inside the glovebox.

Tbe system does need initialising after changing a tyre, tyre pressures, etc.

 

It is in the original post, I do reset it every single time. 
And it still happens….🙄

[Dave the aygo]

If the car is still under warranty take it back and ask them to find the problem they have got the technology so they say they should find out what the issue is 

 

[G-Hal]

31 minutes ago, Dave the aygo said:

If the car is still under warranty take it back and ask them to find the problem they have got the technology so they say they should find out what the issue is 

 

I’m booked in for the 19th. 
It came on again yesterday, checked the tyre pressures, all good, reset it and it came on again this afternoon. 
 

Next week, they will be told in no uncertain terms that I will not be taking my car away from their garage until the problem is identified and fixed. 
Apart from this issue it’s a cracking little car and I love it, I intend on keeping it for many years to come. I really look after any car I have so this is bugging me so badly 🤣

[martswain]

With a 21 plate Aygo adjusting the tyre pressures will not require a reset as the system only works dynamically whilst the vehicle is moving and comparing the wheel rotation/slip rates via the ABS sensors.

If you are not getting the system fault indication, one minute of flashing and then a solid light every time you start the car but it comes on whilst driving then that would indicate a sensor fault.