Trooper LS V6-3.5L (1998)
Engine Control Module: Symptom Related Diagnostic Procedures
Circuit Description
The powertrain control module (PCM) monitors various sensors to determine the engine operating conditions. The PCM controls fuel delivery, spark
advance, transmission operation, and emission control device operation based on the sensor inputs.
The PCM provides a sensor ground to all of the sensors. The PCM applies 5 volts through a pull-up resistor, and determines the status of the following
sensors by monitoring the voltage present between the 5-volt supply and the resistor:
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The engine coolant temperature (ETC) sensor
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The intake air temperature (IAT) sensor
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The transmission fluid temperature (TFT) sensor The PCM provides the following sensors with a 5-volt reference and a sensor ground signal:
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The exhaust gas recirculating (EGR) pintle position sensor
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The throttle position (TP) sensor
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The manifold absolute pressure (MAP) sensor
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The G Sensor (Rough Road Sensor)
The PCM monitors the separate feedback signals from these sensors in order to determine their operating status.
Diagnostic Aids
IMPORTANT: Be sure to inspect PCM and engine grounds for being secure and clean.
A short to voltage in one of the sensor input circuits may cause one or more of the following DTCs to be set:
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P0108/P1106
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P0113/P1111
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P0118/P1115
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P0123/P1121
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P0560
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P0712
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P1393/P1394
IMPORTANT: If a sensor input circuit has been shorted to voltage, ensure that the sensor is not damaged. A damaged sensor will continue to
indicate a high or low voltage after the affected circuit has been repaired. If the sensor has been damaged, replace it.
An open in the sensor ground circuit between the PCM and the splice will cause one or more of the following DTCs to be set:
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P0108/P1106
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P0113/P1111
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P0118/P1115
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P0123/P1121
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P0712
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P1393/P1394
A short to ground in the 5-volt reference A or B circuit will cause one or more of the following DTCs to be set:
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P0107/P1107
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P0122/P1122
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P139O/P1392
An the in the 5-volt reference circuit A, between the PCM and the splice, will cause one or more of the following DTCs to be set:
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P0122/P1122
An the in the 5-volt reference circuit B, between the PCM and the splice, will cause one or more of the following
DTCs to be set:
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P0107/P1107
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P1390/P1392
Check for the following conditions:
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Poor connection at PCM. Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damage
terminals, and a poor terminal-to-wire connection.
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Damaged harness. Inspect the wiring harness for damage. If the harness is not damaged, observe an affected sensor's displayed value on the scan
tool with the ignition "ON" and the engine "OFF" while you move the connectors and the wiring harnesses related to the following sensors:
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IAT
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ECT
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TP
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MAP
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EGR
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TFT
