ABS, TPMS & airbag lights

The ABS and TPMS lights keep coming on intermittently in my 2006 MINI Cooper convertible and, after getting the driver’s seat side bolster repaired, the airbag light is on permanently. I have fitted a new pair of ABS sensors and I am trying to sort out the OBD socket, as it has no power so can’t be interrogated. The MINI had four new tyres fitted by the previous owner, but it has rubber tyre valves and I thought all Tpms-equipped cars had metal valve stems. All of the tyre pressures are spot on. Steve Haywood The tyre pressure monitoring system on your MINI does not have sensors in the tyres and does not strictly check the tyre pressures. It operates by checking the individual wheel speed using the ABS system. If one of the tyres becomes slightly deflated, the rolling speed will vary very slightly from the other three wheels, which flag up the TPMS light. A sudden loss of the pressure should cause the TPMS light to flash. Once the tyre pressures are correct, the system can be reset by pressing and holding the reset button, extinguishing the light. During the next journey, the system will learn and set the parameters.

As you have both the ABS and the TPMS lights illuminated, I suspect the problem may be in the ABS circuits and may well be due to the Canbus wiring. Given there is no power to the OBD socket, it would appear the vehicle has a serious wiring problem that needs to be rectified. This is common with the MINI, and it will need a continuity tester and a lot of patience to test the circuits. The airbag circuit will need to be reset and this will be dependent on the OBD plug connecting correctly.

To summarise, the OBD plug fault is the first problem that needs to be rectified, then the other systems should hopefully fall into place.