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Home >> Chrysler >> 2009 >> PT Cruiser Limited >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> DTCS P0016 To P0133 - Gas >> P0068-Manifold Pressure/Throttle Position Correlation >> Diagnostic Test

Diagnostic Test

  1. ACTIVE DTC 
    NOTE: Diagnose any TP Sensor or MAP Sensor component DTCs before continuing.
    NOTE: If the P0501 - No Vehicle Speed Signal is set long with this DTC, refer to the P0501 diagnostics before continuing.
    NOTE: The throttle plate and linkage should be free from binding and carbon build up.
    NOTE: Make sure the throttle plate is at the idle position.
    1. Ignition on, engine not running.
    2. With a scan tool, read DTCs.

      Is the DTC active at this time?

      Yes 

      • Go to step  2

      No 

  2. VACUUM LEAK 
    NOTE: This code is enabled on engines with a plastic intake manifold and is intended to shut down the engine if a large crack occurs.
    NOTE: A large vacuum leak is most likely the cause of this DTC.
    1. Inspect the Intake Manifold for leaks and cracks.
    2. Inspect the Power Brake Booster for any vacuum leaks.
    3. Inspect the PCV system for proper operation and vacuum leaks.
    4. Inspect the throttle plate to see if it is bent and will close entirely, if it is bent it may need to be replaced.
    5. Inspect the MAP Sensor for proper installation.
    6. Verify the engine is free from any mechanical failures.

      Were any vacuum leaks found?

      Yes 

      No 

      • Go to step  3
  3. RESTRICTED INTAKE AIR SYSTEM 
    1. Inspect the Intake Air system for excessive blockage.
    2. Inspect the air filter.

      Is the air filter plugged, extremely dirty, or is the Intake Air system restricted in any other way?

      Yes 

      • Replace the Air Filter and free the Intake Air system from any foreign material that is causing the blockage.

        Read and record the related Freeze Frame data. Clear the PCM codes and try to duplicate the conditions that originally caused the DTC to set to see if the code returns.

      • Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .

      No 

      • Go to step  4
  4. MAP SENSOR OPERATION 
    1. Start the engine.
    2. With a scan tool, monitor the MAP Sensor voltage.
    3. Snap the throttle.

      Does the MAP Sensor voltage vary from below 2.0 volts at idle to above 3.5 volts at wide open throttle?

      Yes 

      • Go to step  5

      No 

      • Go to step  12
  5. TP SENSOR OPERATION 
    1. Ignition on, engine not running.
    2. With a scan tool, monitor the TP Sensor voltage while slowly pressing the throttle pedal from closed to wide open throttle.

      Does voltage start at approximately 0.8 of a volt and go above 3.5 volts with a smooth transition?

      Yes 

      No 

      • Go to step  6
  6. EXCESSIVE RESISTANCE IN THE TP SENSOR (F855) 5-VOLT SUPPLY CIRCUIT 
    Fig 1: Checking TP Sensor Circuit
    GC0117140Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the TP Sensor harness connector.
    3. Disconnect the C2 PCM 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 PCM Pinout Box 8815 to perform diagnosis.
    4. Measure the resistance of the (F855) 5-volt Supply circuit from the TP Sensor harness connector to the appropriate terminal of special tool #8815.

      Is the resistance below 5.0 ohms?

      Yes 

      • Go to step  7

      No 

  7. TP SENSOR (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking TP Sensor Circuit
    GC0117141Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and (F855) 5-volt Supply circuit in the TP Sensor harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  8
  8. THROTTLE POSITION SENSOR 
    Fig 3: Checking TP Sensor Circuit
    GC0117142Courtesy of CHRYSLER LLC
    1. Connect the C2 PCM harness connector.
    2. Ignition on, engine not running.
    3. With a scan tool, monitor the TP Sensor voltage.
    4. Connect a jumper wire between the (K22) TP Sensor No. 1 Signal circuit and the (K900) Sensor ground circuit in the Sensor harness connector.

      Does the TP Sensor voltage change from approximately 4.9 volts to below 0.5 of a volt with the jumper wire installed?

      Yes 

      No 

      • Go to step  9
        NOTE: Remove the jumper wire before continuing.
  9. EXCESSIVE RESISTANCE IN THE (K22) TP NO. 1 SIGNAL CIRCUIT 
    Fig 4: Checking TP Sensor Circuit
    GC0117143Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the C2 PCM 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 PCM Pinout Box 8815 to perform diagnosis.
    3. Measure the resistance of the (K22) TP Sensor No. 1 Signal circuit from the TP Sensor harness connector to the appropriate terminal of special tool #8815.

      Is the resistance below 5.0 ohms?

      Yes 

      • Go to step  10

      No 

  10. (K22) TP SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 5: Checking TP Sensor Circuit
    GC0117144Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and the (K22) TP Sensor No. 1 Signal circuit in the TP Sensor harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  11
  11. EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT 
    Fig 6: Checking TP Sensor Circuit
    GC0117145Courtesy 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 PCM Pinout Box 8815 to perform diagnosis.
    1. Measure the resistance of the (K900) Sensor ground circuit from the TP Sensor harness connector to the appropriate terminal of special tool #8815.

      Is the resistance below 5.0 ohms?

      Yes 

      • Go to step  18

      No 

  12. EXCESSIVE RESISTANCE IN THE MAP SENSOR (F855) 5-VOLT SUPPLY CIRCUIT 
    Fig 7: Checking TP Sensor Circuit
    GC0117146Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the MAP Sensor harness connector.
    3. Disconnect the C2 PCM 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 PCM Pinout Box 8815 to perform diagnosis.
    4. Measure the resistance of the (F855) 5-volt Supply circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

      Is the resistance below 5.0 ohms?

      Yes 

      • Go to step  13

      No 

  13. MAP SENSOR (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 8: Checking 5-Volt Supply Circuit
    GC0117147Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and the (F855) 5-volt Supply circuit in the MAP Sensor harness connector.

      Is the resistance above 100k ohms?

      Yes 

      • Go to step  14

      No 

  14. MAP SENSOR 
    Fig 9: Checking MAP Sensor Circuit
    GC0117148Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Connect the C2 PCM harness connector.
    3. Ignition on, engine not running.
    4. With a scan tool, monitor the MAP Sensor voltage.
    5. Connect a jumper wire between the (K1) MAP Signal circuit and the (K900) Sensor ground circuit.

      Does the scan tool display MAP voltage from approximately 4.9 volts to below 0.5 of a volt with the jumper wire installed?

      Yes 

      No 

      • Go to step  15
        NOTE: Remove the jumper wire before continuing.
  15. EXCESSIVE RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT 
    Fig 10: Checking MAP Sensor Signal Circuit
    GC0117149Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the C2 PCM 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 PCM Pinout Box 8815 to perform diagnosis.
    3. Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

      Is the resistance below 5.0 ohms?

      Yes 

      • Go to step  17

      No 

  16. (K1) MAP SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 11: Checking MAP Sensor Signal Circuit
    GC0117150Courtesy of CHRYSLER LLC
    1. Measure the resistance between ground and the (K1) MAP Signal circuit in the MAP Sensor harness connector.

      Is the resistance below 100 ohms?

      Yes 

      No 

      • Go to step  17
  17. EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT 
    Fig 12: Checking MAP Sensor Ground Circuit
    GC0117151Courtesy 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 PCM Pinout Box 8815 to perform diagnosis.
    1. Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.

      Is the resistance below 5.0 ohms?

      Yes 

      • Go to step  18

      No 

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

      No