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Home >> Jaguar >> 2004 >> XJ8 Base >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Servicing >> Descriptions & Operation >> Transmission Control Module (TCM) & Main Control Valve Body >> Transmission Electronic System >> Monitoring The Substrate Temperature Sensor
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Monitoring The Substrate Temperature Sensor

The TCM is situated within the transmission on the valve body. As the TCM controls a number of high power solenoids and is surrounded by ATF, the TCM can obviously get very hot. If the temperature of the hardware rises above a pre-determined level the TCM will be shut down. Prior to the TCM shutting down the TCM will log a fault code, during shutdown the transmission will enter mechanical limp-home mode. Monitoring of the substrate temperature is performed by a temperature dependent resistor mounted on the processor.