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Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
  1. 1)  SPEED CONTROL SWITCH VOLTAGE HIGH 
    NOTE: Do not press any of the Speed Control Switch buttons.

    Ignition on, engine not running.

    With a scan tool, read the Speed Control voltage.

    Is the Speed Control voltage above 4.8 volts? 

    Yes 

    1. Go To step  2).

    No 

    1. Refer to INTERMITTENT CONDITION .
    2. Perform POWERTRAIN VERIFICATION TEST .
  2. 2)  SPEED CONTROL SWITCHES 

    Turn the ignition off.

    Remove and disconnect the Speed Control Switches from the steering wheel.

    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 (V371) S/C Switch No.1 Signal and (V397) 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 step  3).

    No 

    1. Replace the Speed Control Switch that had the incorrect resistance value.
    2. Perform POWERTRAIN VERIFICATION TEST .
  3. 3)  STEERING COLUMN CONTROL MODULE 

    Disconnect the C1 and C3 SCCM harness connector per Service Information.

    Measure the resistance of the (V397) Switch Return circuit between the C1 and C3 SCCM harness connectors.

    Measure the resistance of the (V371) S/C Switch No.1 Signal circuit between the C1 and C3 SCCM harness connectors.

    Was the resistance above 5.0 ohms for either circuit? 

    Yes 

    1. Replace the Steering Column Control Module.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  4).
  4. 4)  (V371) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE 
    Fig 1: Checking Speed Control Switch No. 1 Signal Circuit
    GC0027151Courtesy of DAIMLERCHRYSLER CORP.

    Connect the SCCM harness connectors per Service Information.

    Disconnect the C3 PCM harness connector.

    Ignition on, engine not running.

    Measure the voltage on the (V371) S/C Switch No.1 Signal circuit in the Speed Control harness connector.

    Is the voltage above 0 volts? 

    Yes 

    1. Repair the short to battery voltage in the (V371) S/C Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  5).
  5. 5)  (V371) S/C SWITCH NO.1 SIGNAL CIRCUIT OPEN 
    Fig 2: Checking Speed Control Switch No. 1 Signal Circuit
    GC0027153Courtesy of DAIMLERCHRYSLER CORP.
    NOTE: The measurement must be taken from both Speed Control Switch harness connectors.

    Turn the ignition off.

    Disconnect the C3 SCCM harness connector.

    Measure the resistance of the (V371) S/C Switch No.1 Signal circuit from the S/C Switch harness connectors to the C3 SCCM harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To step  6).

    No 

    1. Repair the open in the (V371) S/C Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. 6)  (V71) S/C SWITCH NO.1 SIGNAL CIRCUIT OPEN 
    Fig 3: Checking Speed Control Switch No. 1 Signal Circuit
    GC0027154Courtesy of DAIMLERCHRYSLER CORP.

    Disconnect the C1 SCCM 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 circuit from the C1 SCCM harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms for both measurements? 

    Yes 

    1. Go To step  7).

    No 

    1. Repair the open in the (V71) S/C Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  7. 7)  (V397) SWITCH RETURN CIRCUIT OPEN 
    Fig 4: Checking Speed Control Switch Return Circuit
    GC0027155Courtesy of DAIMLERCHRYSLER CORP.
    NOTE: The measurement must be taken from both Speed Control Switch harness connectors.

    Measure the resistance of the (V397) Switch Return circuit from the S/C Switch harness connector to the C3 SCCM harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To step  8).

    No 

    1. Repair the open in the (V397) Switch Return circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  8. 8)  (V937) SWITCH RETURN CIRCUIT OPEN 
    Fig 5: Checking Speed Control Switch Return Circuit
    GC0027156Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance of the (V937) Switch Return circuit from the C1 SCCM harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms for both measurements? 

    Yes 

    1. Go To step  9).

    No 

    1. Repair the open in the (V937) Switch Return circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  9. 9)  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 (V371) S/C Switch No.1 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 value? 

    Yes 

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

    No 

    1. Go To step  10).
  10. 10)  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 .
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