DaimlerChrysler Jeep Grand Cherokee 2002 Service Manual page 146

DRIVEABILITY - DIESEL
P0641-SENSOR REFERENCE VOLTAGE A CKT VOLTAGE TOO LOW —
Continued
TEST
3 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Turn the ignition on.
Measure the voltage of the Sensor Reference Voltage A circuit.
Is the voltage above 4.8 volts?
Yes → Replace the Mass Air Flow Sensor.
→ Go To 4
No
4 Turn the ignition off.
Disconnect the Accelerator Pedal Position Sensor harness connector.
Turn the ignition on.
Measure the voltage of the Sensor Reference Voltage A circuit.
Is the voltage above 4.8 volts?
Yes → Replace the Accelerator Pedal Position Sensor.
→ Go To 5
No
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the MAF Sensor and Accelerator Pedal Position Sensor harness connec-
tors.
Measure the resistance between ground and the Sensor Reference Voltage A circuit.
Is the resistance above 100 kohms?
Yes → Go To 6
→ Repair the Sensor Reference Voltage A circuit for a short to
No
6 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the MAF Sensor harness connector.
Measure the resistance between the Sensor Reference Voltage A circuit and the MAF
Sensor Ground circuit.
Disconnect the Accelerator Pedal Position Sensor harness connector.
Measure the resistance between the Sensor Reference Voltage A circuit and both
Accelerator Pedal Position Sensor Ground circuits.
Is the resistance above 100 kohms for each measurement?
Yes → Go To 7
→ Repair the Sensor Reference Voltage A circuit for a short to the
No
ACTION
Perform ROAD TEST VERIFICATION - VER-2.
Perform ROAD TEST VERIFICATION - VER-2.
ground.
Perform ROAD TEST VERIFICATION - VER-2.
Sensor Ground circuit that measured below 100 kohms.
Perform ROAD TEST VERIFICATION - VER-2.
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APPLICABILITY
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