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Home › Jeep › 2009 › Commander Overland, 4WD › Repair and Diagnosis › Engine Performance › System › DTCS P0507 To P0600 - NGC › P0579-Speed Control Switch 1 Performance › Diagnostic Test

Diagnostic Test

  1. ACTIVE DIAGNOSTIC TROUBLE CODE (DTC) 
    1. Start the engine and allow it to idle for at least 60 seconds.
      WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.
      NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.
    2. Using the scan tool, select View DTCs.

      Is the DTC Active at this time?

      Yes 

      • Go to step  2

      No 

  2. SPEED CONTROL SWITCH 
    1. Turn the ignition off.
    2. Disconnect the Speed Control Switch harness connector in accordance with the Service Information.
    3. Measure the resistance between (V71) S/C Switch Sense 1 circuit and the (V937) Switch Return circuit.
    4. Monitor the Ohmmeter while pressing each function button on each switch.
    5. The following resistance specs are taken between terminals (V71) S/C Switch Sense 1 circuit and the (V937) Switch Return circuit of the switch when holding the switch button in the following position:
      • Not pressing any switch - 20.5 kOhms
      • On/Off - 0.47 kOhms
      • Set/Decel - 4.34 kOhms
      • Cancel - 1.24 kOhms
      • Resume/Accel - 8.80 kOhms

      Does the function on the Speed Control Switch have the correct resistance value +/- 0.2 of an Ohm?

      Yes 

      • Go to step  3

      No 

  3. (V71) S/C SWITCH SENSE 1 CIRCUIT SHORTED TO VOLTAGE 
    Fig 1: Measuring Voltage On S/C Switch Sense Circuits In Clockspring Harness Connector
    GC0094907Courtesy of CHRYSLER LLC
    1. Disconnect the C3 PCM harness connector.
    2. Disconnect the C2 Clockspring harness connector in accordance with the Service Information.
    3. Ignition on, engine not running.
    4. Measure the voltage on the (V71) S/C Switch Sense 1 circuit in the C2 Clockspring harness connector.

      Is there any voltage present?

      Yes 

      No 

      • Go to step  4
  4. (V71) S/C NO. 1 SWITCH SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 2: Measuring Resistance Between Ground And S/C Switch Sense Circuit In SCM Harness Connector
    GC0094908Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Measure the resistance between ground and the (V71) S/C Switch Sense 1 circuit in the C2 SCM harness connector.

      Is the resistance below 100 Ohms?

      Yes 

      No 

      • Go to step  5
  5. (V71) S/C SWITCH SENSE 1 CIRCUIT SHORTED TO THE (V937) S/C SWITCH RETURN CIRCUIT 
    Fig 3: Measuring Resistance Between S/C Switch Sense Circuit And S/C Switch Return Circuit In Clockspring C2 Harness Connector
    GC0094909Courtesy of CHRYSLER LLC
    1. Measure the resistance between the (V71) S/C Switch Sense 1 circuit and the (V937) S/C Switch Return circuit in the C2 SCM harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Go to step  6
  6. CLOCKSPRING 
    1. Measure the resistance of the (V71) S/C Switch Sense 1 circuit between the C2 and C8 SCM connections.
    2. Measure the resistance of the (V937) Switch Return circuit between the C2 and C8 SCM connections.

      Is the resistance above 5.0 Ohms for either reading?

      Yes 

      No 

      • Go to step  7
  7. STEERING WHEEL JUMPER HARNESS 
    Fig 4: Measuring Resistance Of S/C Switch Sense 1 Circuit Switch Return Circuit Between Clockspring Harness Connector And S/C Switch Harness Connector
    GC0094910Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Measure the resistance of the (V71) S/C Switch Sense 1 circuit between the C8 Clockspring harness connector and S/C Switch harness connector.
    3. Measure the resistance of the (V937) Switch Return circuit between the C8 Clockspring harness connector and S/C Switch harness connector.

      Is the resistance above 5.0 Ohms for either reading?

      Yes 

      No 

      • Go to step  8
  8. (V71) S/C SWITCH SENSE 1 CIRCUIT OPEN 
    Fig 5: Measuring Resistance Of S/C Switch Sense Circuit From C2 Clockspring Harness Connector To Appropriate Terminal Of PCM Pinout Box 8815
    GC0094911Courtesy of CHRYSLER LLC
    CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 to perform diagnosis.
    1. Measure the resistance of the (V71) S/C Switch Sense 1 circuit from the C2 Clockspring harness connector to the appropriate terminal of PCM Pinout Box 8815.

      Is the resistance below 5.0 Ohms for both measurements?

      Yes 

      • Go to step  9

      No 

  9. (V937) SWITCH RETURN CIRCUIT OPEN 
    Fig 6: Measuring Resistance Of S/C Switch Return Circuit From Clockspring C2 Harness Connector To Appropriate Terminal Of PCM Pinout Box 8815
    GC0094912Courtesy of CHRYSLER LLC
    1. Measure the resistance of the (V937) Switch Return circuit from the C2 Clockspring harness connector to the appropriate terminal of PCM Pinout Box 8815.

      Is the resistance below 5.0 Ohms for both measurements?

      Yes 

      • Go to step  10

      No 

  10. SPEED CONTROL SWITCH VOLTAGE VALUES 
    CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 and PCM Pinout Box Adapter 8815-1 to perform diagnosis.
    1. Install the PCM Pinout Box 8815-1 on the C3 PCM harness connector.
    2. Connect the S/C Switch harness connectors.
    3. Connect the Clockspring harness connectors.
    4. Turn the ignition on.
    5. Using the scan tool, monitor the S/C Switch voltage readings.
    6. Using a Voltmeter check the voltage on the (V71) S/C Switch Sense 1 circuit and the (V72) S/C Switch Sense 2 circuit at the appropriate terminals of the PCM Pinout Box 8815.
    7. Monitor the Voltmeter.
    8. Using the scan tool, monitor the S/C Switch voltage readings.
      SWITCH POSITION  SWITCH No. 1 VOLTAGE VALUE  SWITCH No. 2 VOLTAGE VALUE 
      NO SWITCHES PRESSED 4.31 to 4.78 Volts 4.31 to 4.78 Volts
      ON/OFF PRESSED 0.59 to 1.13 Volts 3.53 to 3.92 Volts
      RES/ACCEL PRESSED 3.88 to 4.17 Volts 2.04 to 2.47 Volts
      SET/DECEL PRESSED 3.16 to 3.56 Volts 1.17 to 1.56 Volts
      CANCEL PRESSED 1.59 to 1.99 Volts 2.84 to 3.25 Volts
    9. Compare the voltage readings on the Voltmeter to what the scan tool displayed.

      Are the voltage readings out of the listed specification and is there less than a 0.2 of a Volt difference between the Voltmeter switch values and the scan tool switch value?

      Yes 

      No 

      • Go to step  11
  11. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Speed Control Switch and the Powertrain Control Module (PCM).
    2. Look for any chafed, pierced, pinched or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      No 

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