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Home >> Jaguar >> 2004 >> XJ8 Base >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Servicing >> Descriptions & Operation >> Transmission Control Module (TCM) & Main Control Valve Body >> Transmission Electronic System >> Plausibility Checking
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Plausibility Checking

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.