FAO Those with tyre pressure warnings

[StevenRB45]

When do they actually go off?

Our ds3 doesn't have a particularly rigorous maintenance regime for various reasons but anyway both me and the car were in the same place in daylight and I did the tyre pressures for first time in a while. All 4 wheels were 5 PSI down and not a peep out of the warning, do they only work if the wheel is flat at the bottom? As far as I know I've followed the directions to the letter, I.e. set the pressures then reset the system on the car computer screen but it's never actually done anything.

[cyclone]

It will go off when say 1 of the tires is low but if they are all the same then it would not. That has to do with how it senses that a tire is low. The system uses the tire speed sensor to compare all 4 tires speed and when a tire has low air pressure then it will have a different circumference so that 1 tire would be going at a slightly different speed than the other three setting off the warning. This is also the reason that you need to reinitialize the system after adding air to the tires.

[Bigfeet]

As Cyclone said the system does NOT record the pressures, it is mechanical in operation.

There is a tolerance built into the system to take into account different loads and temperature so the change in pressure does need to be a large one before the system fires.

[StevenRB45]

Thanks gents, Tbf it might be a side effect of the low profile Michelin's as well guess it takes quite a drop in pressure for them to flex compared to balloon tyres. Shall keep a closer eye in future.

[shifta]

The last time my system beeped its was 11psi down from 38psi

[Sash]

Mines been going loopy since having 2 tyres fitted. have checked and reset system about 6 times now. :mad: