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Home >> Dodge and Ram >> 2002 >> Durango Base, 5.9 Z, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - NGC >> Diagnostic Tests >> DTC P0579: Speed Control Switch #1 Performance >> Testing

DTC P0579: Speed Control Switch #1 Performance: Testing

  1. Turn the ignition on, with the engine off. With the DRBIII(R), monitor each function of the S/C Switches. Press and release each S/C Switch.
    • Resume/Accel
    • Cancel
    • Coast/Decel
    • On/Off
    • Set

    Does each S/C switch function change status when pressing and then releasing each switch? If yes, see INTERMITTENT FAILURES  under ON-BOARD DIAGNOSTICS. If no, go to next step.

    2. WARNING: Deactivate air bag system before performing any service operation. See appropriate AIR BAG RESTRAINT SYSTEMS article. DO NOT apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.
  2. Turn the ignition off. Remove the S/C Switches from the steering wheel. Measure the resistance across each S/C Switch (component side). Monitor the ohmmeter while pressing each function button on each switch. Does the function on the S/C Switches have the correct resistance value? See SPEED CONTROL SWITCH RESISTANCE SPECIFICATIONS  table. If yes, go to next step. If no, replace the S/C Switch that has the incorrect resistance value.
    SPEED CONTROL SWITCH RESISTANCE SPECIFICATIONS

    Application Ohms
    Cancel 900-918
    Coast (Decel) 2910-2970
    On/Off Zero
    Resume/Accel 15,400
    Set 6584-6716
  3. Disconnect the PCM harness connectors. Measure the resistance between the S/C Switch Signal circuit and the Sensor Ground circuit in each S/C Switch harness connector. Is the resistance less than 5.0 ohms? If yes, repair the short between the S/C Switch Signal circuit and the Sensor Ground circuit. If no, go to next step.
  4. Measure the voltage on the S/C Switch Signal circuit in each S/C Switch harness connector. Is the voltage more than 5.0 volts? If yes, repair the short to battery voltage in the S/C Signal circuit. If no, go to next step.
  5. Measure the resistance between ground and the S/C Switch Signal circuit at each S/C Switch harness connector. Is the resistance less than 100 ohms? If yes, repair the short to ground in the S/C Switch Signal circuit. If no, go to next step.
    6. 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.
  6. Measure the resistance of the S/C Switch Signal circuit from each S/C Switch harness connector to the appropriate terminal in the Miller Special Tool. Is the resistance less than 5.0 ohms? If yes, go to next step. If no, repair the open in the S/C Switch Signal circuit.
    7. 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.
  7. Measure the resistance of the Sensor Ground circuit from each S/C Switch harness connector to the appropriate terminal in the Miller Special Tool. Is the resistance less than 5.0 ohms? If yes, go to next step. If no, repair the open in the Sensor Ground circuit.
    8. NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push-out. Repair as necessary.
  8. There are no possible causes remaining, replace the PCM.
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