Trooper S 4WD V6-3.5L (2002)
Step 5 - 6
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart:
2. If the MIL does not remain "ON" when the PCM is disconnected, the MIL driver wiring is not faulty.
3. If the MIL driver circuit is OK, the instrument panel cluster is faulty.
6. This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read only memory (EEPROM). When the PCM is
replaced, the new PCM must be programmed. Refer to PCM Replacement and Programming Procedures in Powertrain Control Module (PCM)
and Sensors.
No Malfunction Indicator Lamp (MIL)
No Malfunction Indicator Lamp (MIL)
Circuit Description
The "Check Engine" lamp (MIL) should always be illuminated and steady with the ignition "ON" and the engine stopped. Ignition feed voltage is
supplied to the MIL bulb through the meter fuse. The powertrain control module (PCM) turns the MIL "ON" by grounding the MIL driver circuit.
Diagnostic Aids
An intermittent MIL may be cased by a poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check for the following
items:
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Inspect the PCM harness and connections for improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire
connection, and damaged harness.
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If the engine runs OK, check for a faulty light bulb, an open in the MIL driver circuit, or an open in the instrument cluster ignition feed.
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If the engine cranks but will not run, check for an open PCM ignition or battery feed, or a poor PCM to engine ground.