LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chrysler >> 2009 >> Sebring Base, 2D Convertible, EDG >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0503 To P060B - GPEC >> P0579-Speed Control Switch 1 Performance >> Diagnostic Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Test

  1. DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE 
    NOTE: Use the following table as a reference when diagnosing speed control switch voltage DTCs. Compare the voltage readings displayed on the scan tool with the values in the table.
    - Switch 1 voltage (V71)  Switch 2 voltage (V72) 
    On/Off - Min. 0.5882 3.5294
    On/Off - Max. 1.1373 3.9216
    Set - Min. 3.1569 1.1765
    Set - Max. 3.5686 1.5686
    Cancel - Min. 1.5882 2.8431
    Cancel - Max. 2.0000 3.2549
    Accel - Min. 3.8824 2.0392
    Accel - Max. 4.1765 2.4706
    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 may 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. With a scan tool, select View DTCs.

      Is the status Active for this DTC?

      Yes 

      • Go to step  2

      No 

  2. SPEED CONTROL SWITCH 
    Fig 1: Checking S/C Circuit
    GC0099971Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
      NOTE: The steering wheel airbag must be removed to access the speed control switch connector. Refer to the appropriate Service information prior to removing the steering wheel airbag.
    2. Disconnect the Speed Control Switch harness connector.
      NOTE: When checking circuits, be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.
    3. Turn the ignition on.
    4. With a scan tool, read the (V71) S/C Signal 1 voltage.
      NOTE: The (V71) S/C Signal 1 voltage should be above 4.8 Volts with the Speed Control Switch disconnected.
    5. Connect a jumper wire between the (V71) S/C Signal 1 circuit and the (V937) S/C Switch Ground circuit in the Speed Control Switch harness connector.
    6. With a scan tool, read the (V71) S/C Signal 1 voltage.
      NOTE: The (V71) S/C Signal 1 voltage should be below 0.2 of a Volt with the jumper wire in place.

      Is the (V71) S/C Signal 1 voltage above 4.8 Volts with the Speed Control Switch disconnected and below 0.2 of a Volt with the jumper wire in place?

      Yes 

      No 

      • Go to step  3
  3. SPEED CONTROL SWITCH WIRING HARNESS 
    1. Turn the ignition off.
    2. Disconnect the Clockspring C8 harness connector.
      NOTE: When checking circuits at the Clockspring, be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.
    3. Turn the ignition on.
    4. With a scan tool, read the (V71) S/C Signal 1 voltage.
      NOTE: The voltage should be above 4.8 Volts with the Clockspring C8 connector disconnected.
    5. Connect a jumper wire between the (V71) S/C Signal 1 circuit and the (V937) S/C Switch Ground circuit at the Clockspring C8 connector, not at the harness connector.
    6. With a scan tool, read the (V71) S/C Signal 1 voltage.
      NOTE: The (V71) S/C Signal 1 voltage should be below 0.2 of a Volt with the jumper wire in place.

      Are the Speed Control voltages displayed as described?

      Yes 

      No 

      • Go to step  4
  4. CLOCKSPRING 
    Fig 2: Checking S/C Circuit
    GC0099563Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the Clockspring C2 harness connector.
    3. Turn the ignition on.
    4. With a scan tool, read the (V71) S/C Signal 1 voltage.
      NOTE: The voltage should be above 4.8 Volts with the connector disconnected.
    5. Connect a jumper wire between the (V71) S/C Signal 1 circuit and the (V937) S/C Switch Ground circuit in the Clockspring C2 harness connector.
    6. With a scan tool, read the (V71) S/C Signal 1 voltage.
      NOTE: The (V71) S/C Signal 1 voltage should be below 0.2 of a Volt with the jumper wire in place.

      Are the Speed Control voltages displayed as described?

      Yes 

      No 

      • Go to step  5
  5. (V71) S/C SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE 
    Fig 3: Measuring Voltage On S/C Switch Sense Circuits In Clockspring Harness Connector
    GC0094907Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the Powertrain Control Module (PCM) harness connector.
    3. Turn the ignition on.
    4. Measure the voltage of the (V71) S/C Signal 1 circuit in the Clockspring harness connector.

      Is there any voltage present?

      Yes 

      No 

      • Go to step  6
  6. (V71) S/C SIGNAL 1 CIRCUIT SHORTED TO GROUND 
    Fig 4: 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 Signal 1 circuit in the Clockspring harness connector.

      Is the resistance above 100 Ohms?

      Yes 

      • Go to step  7

      No 

  7. (V71) S/C SIGNAL 1 CIRCUIT SHORTED TO THE (V937) S/C SWITCH GROUND CIRCUIT 
    Fig 5: 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 Signal 1 circuit and the (V937) S/C Switch Ground circuit in the Clockspring C2 harness connector.

      Is the resistance above 100 Ohms?

      Yes 

      • Go to step  8

      No 

  8. (V71) S/C SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE 
    Fig 6: Checking S/C Circuit
    GC0099972Courtesy of CHRYSLER LLC
    NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.
    1. Measure the resistance of the (V71) S/C Signal 1 circuit between the Clockspring C2 harness connector and the Powertrain Control Module (PCM) harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go to step  9

      No 

  9. (V937) S/C SWITCH GROUND CIRCUIT OPEN OR HIGH RESISTANCE 
    Fig 7: Checking S/C Circuit
    GC0099973Courtesy of CHRYSLER LLC
    NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.
    1. Measure the resistance of the (V937) S/C Switch Ground circuit between the Clockspring C2 harness connector and the Powertrain Control Module (PCM) harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go to step  10

      No 

  10. 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.
    4. Perform any Technical Service Bulletins that may apply.

      Were any problems found?

      Yes 

      No