I have a 2006 650i cabriolet. The TPM often indicates the right front tire is low on air. Sometimes the left front about five percent of the time, but never the rear tires. Pressure is never low. After about three resets the problem goes away. I change winter wheels/tires seasonally, but still the TPM indicates the right front tire is low, so it does not appear to be the sensor in the wheel. This happens more frequently when nights are cold and days are relatively warm. Any ideas?
Correct me if I'm wrong, but I'm not sure if the '06 comes with a sensor in the wheel. It still requires the use of the ABS sensor, based on the numbers of rotation of the wheel to determine if one tire has less pressure than the other. A couple of questions: Are these stock tire sizes or have you upgraded either end to a larger/smaller tire? Also, tires can lose as much as 1 PSI of pressure for every 10 degrees change in ambient temperature, it could be as much as 4-5 PSI change which may be enough to trigger sensor based TPMS.
