Plausibility Checking
WARNING: This page is about a different car, the 2005 Jaguar XJR, 2005 Jaguar XJ8, 2004 Jaguar XJR, and 2004 Jaguar XJ8. However, it is still accessible from the selected car via links, so may be relevant.
The TCM detects a fault if an excessive voltage jump is identified between any two consecutive measurements. Also, with the engine started from cold the transmission fluid temperature will start to rise. Therefore the substrate or fluid temperature will also start to rise because the TCM is surrounded by transmission fluid. If the engine and output shaft speed is higher than a set threshold for a predetermined length of time without the substrate temperature rising above a set threshold a fault will be detected.