Model based Rationality Check

P0071 

A model based rationality check of the temperature signal that the ECU receives via the CAN bus is performed by comparing it with the ambient air temperature that is modeled as indicated in Fig 1.

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

Courtesy of BMW OF NORTH AMERICA, INC.

A plausibility fault TUMP is set when the difference (positive) between the measured and the modeled ambient air temperature exceeds a calibrated threshold for a calibrated time. A signal fault TUMP is set when the difference (negative) between the measured and the modeled ambient air temperature lies below a calibrated threshold for a calibrated time.