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Home >> Jeep >> 2007 >> Liberty Limited, RWD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0503 To P060B - Gas >> P0585-Speed Control Switch 1/2 Correlation >> Diagnostic Test

Diagnostic Test

  1. 1) ACTIVE DTC 
    NOTE: This DTC is a two trip fault. If the scan tool indicates a one trip failure, the possible cause may have been the customer pressing both switches simultaneously. Test drive the vehicle and activate the Speed Control system. If the DTC matures to an active fault a repair is necessary.

    Ask the customer if it is possible that two buttons were pressed at the same time before this DTC set. If this is the case, no repair is necessary.

    Start the engine.

    Allow the engine to reach normal operating temperature.

    With a scan tool, select View DTCs.

    NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

    Is the DTC Active or Pending at this time? 

    Yes 

    1. Go to  2).

    No 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.
  2. 2) SPEED CONTROL ON/OFF SWITCH 

    With the scan tool, monitor the Speed Control Switch voltage.

    Disconnect the Speed Control On/Off Switch harness connector.

    Did the voltage change to above 4.8 volts? 

    Yes 

    1. Replace the Speed Control On/Off Switch.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  3).
  3. 3) SPEED CONTROL RESUME/ACCEL SWITCH 

    With the scan tool, monitor the Speed Control Switch voltage.

    Disconnect the Speed Control Resume/Accel Switch harness connector.

    Did the voltage change to above 4.8 volts? 

    Yes 

    1. Replace the Speed Control Resume/Accel Switch.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  4).
  4. 4) SPEED CONTROL SWITCHES 

    Turn the ignition off.

    Remove and disconnect the Speed Control Switches from the steering wheel per Service Information.

    Measure the resistance across each Speed Control Switch.

    Monitor the ohmmeter while pressing each function button on each switch.

    The following resistance specs are taken between terminals (V38) S/C Switch No.2 Signal and (K914) S/C Switch Return circuits of the Switch when holding the switch button in the following position.

    Not pressing any switch - 20.5 kohms

    On/Off - 8.87 kohms

    Set - 0.825 kohms

    Coast - 0.47 kohms

    Cancel - 3.92 kohms

    Resume/Accel - 1.87 kohms

    The following resistance specs are taken between terminals (V37) S/C Switch No.1 Signal and (K914) S/C Switch Return circuits 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 - 5.49 kohms

    Coast - 2.94 kohms

    Cancel - 1.24 kohms

    Resume/Accel - 15.4 kohms

    Does the function on the Speed Control Switches have the correct resistance value? 

    Yes 

    1. Go to  5).

    No 

    1. Replace the Speed Control Switch that had the incorrect resistance value.
    2. Perform POWERTRAIN VERIFICATION TEST .
  5. 5) S/C SWITCH SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 1: Checking Speed Control Switch No. 1 Signal Circuit For Short To Voltage
    GC0056806Courtesy of CHRYSLER LLC
    Fig 2: Checking For Short To Voltage In No. 2 Signal Circuit
    GC0056807Courtesy of CHRYSLER LLC

    Disconnect the C3 PCM harness connector.

    Measure the voltage on the (V37) and (V38) S/C Switch Signal circuits at both Speed Control harness connectors.

    Is the voltage above 5.0 volts? 

    Yes 

    1. Repair the short to voltage in the (V37) or (V38) S/C Switch Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  6).
  6. 6) CLOCKSPRING 
    Fig 3: Measuring Resistance Of Speed Control Switch No. 1 Signal Circuit Between C1 & C4 Clockspring Connections
    GC0056809Courtesy of CHRYSLER LLC
    Fig 4: Checking Resistance Of Switch Return Circuit Between C1 & C4 Clockspring Connections
    GC0056808Courtesy of CHRYSLER LLC
    Fig 5: Measuring Resistance Of Switch Return Circuit Between C1 & C4 Clockspring Connections
    GC0056810Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C1 and C3 Clockspring harness connectors per Service Information.

    Measure the resistance of the (V37) and (V38) S/C Switch Signal circuits between the C1 and C3 Clockspring connectors.

    Measure the resistance of the (K914) Switch Return circuit between the C1 and C3 Clockspring harness connectors.

    Is the resistance above 5.0 ohms for any one of the measurements? 

    Yes 

    1. Replace the Clockspring per Service Information.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  7).
      NOTE: Connect the Clockspring harness connectors per Service Information before continuing.
  7. 7) S/C SWITCH SIGNAL CIRCUIT OPEN 
    Fig 6: Checking For Open In Speed Control Switch Signal Circuits
    GC0056811Courtesy of CHRYSLER LLC
    Fig 7: Measuring Resistance Of Speed Control Switch Signal Circuits From Both Speed Control Harness Connectors To Special Tool Appropriate Terminals
    GC0056812Courtesy 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 Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (V37) and (V38) S/C Switch Signal circuits from both Speed Control harness connectors to the appropriate terminals of special tool #8815.

    Is the resistance below 5.0 ohms for each measurement? 

    Yes 

    1. Go to  8).

    No 

    1. Repair the excessive resistance in the (V37) or (V38) S/C Switch Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  8. 8) (K914) SWITCH RETURN CIRCUIT OPEN 
    Fig 8: Checking Switch Return Circuit For Open
    GC0056813Courtesy of CHRYSLER LLC
    NOTE: The measurement must be taken from both Speed Control Switch harness connectors.

    Measure the resistance of the (K914) Switch Return circuit from both Speed Control harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms for both measurements? 

    Yes 

    1. Go to  9).

    No 

    1. Repair the excessive resistance in the (K914) Switch Return circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  9. 9) S/C SWITCH SIGNAL CIRCUITS SHORTED TO THE (K914) SWITCH RETURN CIRCUIT 
    Fig 9: Checking Speed Control Switch No. 2 Signal Circuit For Short To Switch Return Circuit
    GC0056814Courtesy of CHRYSLER LLC
    Fig 10: Checking For Short To Between Speed Control Switch No. 2 Signal Circuit & Switch Return Circuit
    GC0056773Courtesy of CHRYSLER LLC

    Measure the resistance between the (K914) Switch Return circuit and both of the (V37) and (V38) S/C Switch Signal circuits in the S/C Switch harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the short between the (K914) Switch Return circuit and the (V37) or (V38) S/C Switch Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  10).
  10. 10) (V37 S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V38) S/C SWITCH NO.2 SIGNAL CIRCUIT 
    Fig 11: Measuring Resistance Between Speed Control Switch No. 1 Signal Circuit & Switch No. 2 Signal Circuit At Both Speed Control Harness Connectors
    GC0056815Courtesy of CHRYSLER LLC

    Measure the resistance between the (V37) S/C Switch No.1 Signal circuit and the (V38) S/C Switch No.2 Signal circuit at both Speed Control harness connectors.

    Is the resistance below 100 ohms for each circuit? 

    Yes 

    1. Repair the short between the (V38) S/C Switch No.2 Signal circuit and the (V37) S/C Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  11).
  11. 11) S/C SWITCH SIGNAL CIRCUITS SHORTED TO GROUND 
    Fig 12: Checking Speed Control Switch No. 1 Signal Circuit For Short To Ground
    GC0056816Courtesy of CHRYSLER LLC
    Fig 13: Checking For Short To Ground In Speed Control Switch No. 2 Signal Circuit
    GC0056771Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (V37) and (V38) S/C Switch Signal circuits at both S/C Switch harness connectors.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (V37) or (V38) S/C Switch Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  12).
  12. 12) SPEED CONTROL SWITCH VOLTAGE VALUES 

    Allow the engine to idle.

    With a 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 PRESSED 3.16 to 3.56 volts 1.17 to 1.56 volts
    COAST PRESSED 2.57 to 2.94 volts 0.77 to 1.09 volts
    CANCEL PRESSED 1.59 to 1.99 volts 2.84 to 3.25 volts

    Take these same voltage measurements with a voltmeter by back probing the (V37) S/C Switch No.1 Signal circuit and the (V38) S/C Switch No.2 Signal circuit at the switches.

    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 values? 

    Yes 

    1. Replace the Speed Control Switch.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  13).
  13. 13) PCM 
    NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage or terminal push out. Repair as necessary.

    Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Replace and program the Powertrain Control Module per Service Information.
    2. Perform POWERTRAIN VERIFICATION TEST .