TPMS (tyre pressure monitoring systems) are becoming quite common on modern vehicles and are a significant boost to vehicle safety; especially for motorists with runflat tyres and those who infrequently check their tyre pressures.
Basically the TPMS operates by constantly checking a vehicles tyre pressures to ensure they are within the range set by the vehicle’s manufacturer. You may be thinking all of this is superfluous because punctured tyres tend to be self evident, but that is definitely not so with runflat tyres and the TPMS gives an early warning that tyres are deflating, giving the motorist a chance to rectify the situation before the tyre is damaged or a dangerous situation arises.
A correctly operating TPMS is essential when a vehicle is fitted with runflat tyres as they look and drive normally even when full deflated. Run flat tyres are designed to enable a motorist to drive straight to a tyreshop when the TPMS detects low air pressure so the tyre can be promptly repaired or replaced. If you drive a deflated runflat tyre for more than say 20 to 30 kms, it will be destroyed and the purchase of a new, and often very expensive tyre, will be essential.
The TPMS symbol illuminates on the vehicles dashboard when it is activated by low, or high, tyre air pressure. After repair or replacement of the problem tyre, the TPMS will often be extinguished, but on some vehicles may only disappear driving for a while. On other vehicles you may need to reset the TPMs yourself by following instructions in the handbook and on others you may need to have it reset by a mechanical or auto electrical workshop.
Vehicles with TPMS symbols illuminated are not WOF compliant and will fail a WOF test. In some instances the TPMS sensor in the wheel will need to be replaced. Original equipment items can be very expensive, but fortunately there are now some relatively reasonably priced aftermarket sensors available that can be programmed to match the original equipment part.
The Campaign for Better Tyres is a strong supporter of TPMS tyre pressure monitoring systems and considers that they should be mandatory on all new vehicles.