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Home › Chrysler › 2008 › PT Cruiser Base, 2D Convertible, 2.4 E › Repair and Diagnosis › Engine Performance › System › DTCS P127F To U0168 › P1593-Speed Control Switch Stuck › Diagnostic Test

Diagnostic Test

  1. SPEED CONTROL SWITCH STATUS 

    Start the engine.

    With the DRBIII®, monitor each switch function for the Speed Control Switches.

    Press and release each Speed Control Button.

    - Resume/Accel

    - Cancel

    - Decel (Coast)

    - On/Off

    - Set

    Does each switch function change status when pressing and then depressing each switch? 

    Yes 

    1. Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To  2.
  2. SPEED CONTROL SWITCHES 

    Turn the ignition off.

    Remove the Speed Control Switches from the steering wheel.

    Measure the resistance across each Switch Control Switch.

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

    Resume/Accel - 15,400 ohms

    Cancel - 909 +/- 9 ohms

    Decel (Coast) - 2940 +/- 30 ohms

    On/Off - 0 ohms

    Set - 6650 +/- 66 ohms

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

    Yes 

    1. Go To  3.

    No 

    1. Replace the Speed Control Switch that had the incorrect resistance value.
    2. Perform POWERTRAIN VERIFICATION TEST .
  3. (V71) S/C SWITCH NO. 1 SIGNAL SHORTED TO BATTERY VOLTAGE 
    Fig 1: Measuring For Voltage At S/C Switch No. 1 Signal Circuit
    GC0041722Courtesy of CHRYSLER LLC

    Measure the voltage on the (V71) S/C Switch No. 1 Signal at the Speed Control harness connector.

    Is the is the voltage above 5.0 volts? 

    Yes 

    1. Repair the short to battery voltage in the (V71) S/C Switch No. 1 Signal.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To  4.
  4. (V71) S/C SWITCH NO. 1 SIGNAL OPEN 
    Fig 2: Measuring Resistance Of S/C Switch No. 1 Signal Circuit
    GC0041774Courtesy of CHRYSLER LLC
    NOTE: The measurement must be taken from both Speed Control Switch harness connector.
    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 (V71) S/C Switch No. 1 Signal from the Speed Control harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms for both measurement? 

    Yes 

    1. Go To  5.

    No 

    1. Repair the open in the (V71) S/C Switch No. 1 Signal.
    2. Perform POWERTRAIN VERIFICATION TEST .
  5. V937/K914 S/C SWITCH RETURN OPEN 
    Fig 3: Measuring Resistance Of S/C Switch Return Circuit
    GC0041723Courtesy of CHRYSLER LLC
    NOTE: The measurement must be taken from both Speed Control Switch harness connectors.
    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 V937/K914 S/C Switch Return circuit from the 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  6.

    No 

    1. Repair the open in the V937/K914 S/C Switch Return circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. 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.

    If there are no possible causes remaining, view repair. 

    Repair 

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