Faulty Tyre Pressure Loss Indicator System

6th October 2021


Tire Pressure Loss Indictor Warning Light

When I test drove my GTE before buying it I noticed that the low tire pressure warning light was on. I figured it might just need some air adding or failing that, it might have a slow puncture which needed repairing or even a new tyre.

Once acquired, I adjusted the tyre pressures and resynchronised the system. A few days later the warning light came on again - rear right tyre. The GTE doesn't come with a spare tyre and not having a car without a spare before, I felt it was important I could trust the low pressure loss indicator system. I checked the tyre, adjusted the pressures again and reset the system. But after a few days, the warning light would reappear. I decided I must have a puncture so took the car to a tyre shop. But after checking, they told me they could not find any puncture. So I kept an eye on things and eventually grew more confident that my tyres were actually fine and I did not have any leaks. It must be the warning system that was giving false alerts.

Over time I noticed that, whilst it usually indicated that it was the same (rear-right) tyre which was loosing pressure, sometimes it would report a different tyre. Also, occasionally I have been unable to reset the system after the warning light has appeared. On one occasion the warning light flashed for a while before staying lit which the manual says is an indication of a system fault and I need to seek expert assistance. So I am going to do that, when the car next goes for a service, I'll ask them to invesitigate.

My understanding is that the Tyre Pressure Loss Indicator system uses the ABS wheel speed sensors on each of the 4 wheels. After the system has been synchronised after the tyre pressures have been set correctly, if subsequently it detects that one wheel is rotating faster than the others, then it assumes it must have lost pressure. I therefore suspect that it might be the ABS control module which is at fault! Could be expensive :-(

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