" TPMS lights on causing MOT failures "

Sadly many MOT stations do not interperate the information correctly.

The MOT manual ( now PDF on line not a book as on line its continually updated )

It clearly states the TPMS is only testable on cars first registered after January 2012

If a TPMS light is flashing before becoming continous its a fault, if its just on its indicating low pressure and pass and advise .

So if your car was registered before Jan 2012 swapping winter and summer tyres will not cause an issue with an MOT

Most vehicle ECUs will store data for both winter and summer tyres and specialist equipment allows clonning of TPMS valves so cheap valves can be fitted and clonned very easily. Biggest problems is garages wont invest in TPMS clonning equipment as they dont see the potential due to the fact they dont understand just what it can do.