P0579-S/C Switch Signal Circuit Signal Voltage Too Low - DaimlerChrysler Jeep Grand Cherokee 2002 Service Manual

Symptom:

P0579-S/C SWITCH SIGNAL CIRCUIT SIGNAL VOLTAGE TOO LOW

INTERMITTENT CONDITION
S/C ON/OFF/SET SWITCH
S/C RESUME/ACCEL SWITCH
S/C/ SWITCH SIGNAL CIRCUIT SHORTED TO SENSOR GROUND
S/C SWITCH SIGNAL CIRCUIT SHORTED TO GROUND
ECM
TEST
1 Turn the ignition on.
With the DRBIII , read the S/C Switch voltage.
Is the S/C Switch voltage below 0.4 volt?
Yes → Go To 2
→ Go To 7
No
2 Turn the ignition on.
With the DRBIII , monitor the S/C Switch voltage.
Disconnect the S/C ON/OFF/SET Switch harness connector.
Did the DRB reading change to above 4.7 volts?
Yes → Replace the S/C ON/OFF/SET Switch.
→ Go To 3
No
3 Turn the ignition on.
With the DRBIII , monitor the S/C Switch voltage.
Disconnect the S/C Resume/Accel Switch harness connector.
Did the volt change to above 4.7 volts?
Yes → Replace the S/C Resume/Accel Switch.
→ Go To 4
No
4 Turn the ignition off.
Disconnect the S/C ON/OFF/SET Switch harness connector.
Disconnect the S/C RESUME/ACCEL Switch harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between the S/C Switch Signal circuit and the Sensor Ground
circuit in the ECM harness connector.
Is the resistance below 5.0 ohms?
Yes → Repair the S/C Switch Signal circuit shorted to the Sensor Ground
→ Go To 5
No
POSSIBLE CAUSES
ACTION
Perform SPEED CONTROL VERIFICATION - VER-4.
Perform SPEED CONTROL VERIFICATION - VER-4.
circuit.
Perform SPEED CONTROL VERIFICATION - VER-4.
DRIVEABILITY - DIESEL
127
APPLICABILITY
All
All
All
All