1.15.3.3 Model based rationality check

P0071 (TUMPsig, TUMPnpl) 

A model based rationality check of the temperature signal (via CAN) is performed by comparing the measured ambient air temperature with the model as indicated in Fig 1.

Fig 1: Ambient Air Temperature - Modeled Value Of Ambient Air Temperature

Courtesy of BMW OF NORTH AMERICA, INC.

A TUMPnpl fault will be set if the difference (positive) between the measured and the modeled ambient air temperature exceeds a calibrated threshold for a calibrated period of time. Likewise a TUMPsig fault will be set if the difference (negative) between the measured and the modeled ambient air temperature lies below a calibrated threshold for a calibrated period of time.