Trooper S 4WD V6-3.5L (2002)
Engine Control Module: Description and Operation
PCM Function
PCM Function
The PCM supplies either 5 or 12 volts to power various sensors or switches. The power is supplied through resistances in the PCM which are so high in
value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading
because its resistance is too low.
Therefore, a digital voltmeter with at least 10 megohms input impedance is required to ensure accurate voltage readings. Tool J 39200 meets this
requirement. The PCM controls output circuits such as the injectors, fan relays, etc., by controlling the ground or the power feed circuit through
transistors or through either of the following two devices:
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Output Driver Module (ODM)
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Quad Driver Module (QDM)
