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Home >> Jeep >> 2007 >> Commander Base, 4.7 P, AWD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P1602 To P2123 >> P2074-Map/TPS Correlation - High Airflow/Vacuum Leak Detected >> Diagnostic Test

Diagnostic Test

  1. 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-VEHICLE SPEED SENSOR 1 PERFORMANCE 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.

    Ignition on, engine not running.

    With a scan tool, select View DTCs.

    Is the DTC Active at this time? 

    Yes 

    1. Go to  2).

    No 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.
  2. 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.

    Inspect the Intake Manifold for leaks and cracks.

    Inspect the Power Brake Booster for any vacuum leaks.

    Inspect the PCV system for proper operation and vacuum leaks.

    Inspect the throttle plate to see if it is bent and will close entirely, if it is bent it may need to be replaced.

    Inspect the MAP Sensor for proper installation.

    Verify the engine is free from any mechanical failures.

    Were any vacuum leaks found? 

    Yes 

    1. Repair the vacuum leak as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  3).
  3. 3) MAP SENSOR OPERATION 

    Start the engine.

    With a scan tool, monitor the MAP Sensor voltage.

    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 

    1. Go to  4).

    No 

    1. Go to  11).
  4. 4) TP SENSOR OPERATION 

    Ignition on, engine not running.

    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 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.

    No 

    1. Go to  5).
  5. 5) EXCESSIVE RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT 
    Fig 1: Checking 5-Volt Supply Circuit For Open Or Excessive Resistance
    GC0050876Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the TP Sensor harness connector.

    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 Miller Special Tool #8815 to perform diagnosis.

    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 

    1. Go to  6).

    No 

    1. Repair the excessive resistance in the (F855) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. 6) (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking 5-Volt Supply Circuit For Short To Ground
    GC0050877Courtesy of CHRYSLER LLC

    Measure the resistance between ground and (F855) 5-volt Supply circuit in the TP Sensor harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (F855) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  7).
  7. 7) THROTTLE POSITION SENSOR 
    Fig 3: Connecting Jumper Wire Between No. 1 Signal Circuit And Ground Circuit At TP Sensor Harness Connector
    GC0050878Courtesy of CHRYSLER LLC

    Connect the C2 PCM harness connector.

    Ignition on, engine not running.

    With a scan tool, monitor the TP Sensor voltage.

    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 

    1. Replace the Throttle Position Sensor.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  8).
      NOTE: Remove the jumper wire before continuing.
  8. 8) EXCESSIVE RESISTANCE IN THE (K22) TP NO. 1 SIGNAL CIRCUIT 
    Fig 4: Measuring Resistance Of TP Sensor No. 1 Signal Circuit
    GC0050879Courtesy of CHRYSLER LLC

    Turn the ignition off.

    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 Miller Special Tool #8815 to perform diagnosis.

    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 

    1. Go to  9).

    No 

    1. Repair the excessive resistance in the (K22) TP Sensor No. 1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  9. 9) (K22) TP SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 5: Measuring Resistance Between Ground And TP Sensor No. 1 Signal Circuit
    GC0050880Courtesy of CHRYSLER LLC

    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 

    1. Repair the short to ground in the (K22) TP Sensor No. 1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    Go to step  10).

  10. 10) EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT 
    Fig 6: Measuring Resistance Of Sensor Ground Circuit
    GC0050881Courtesy 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 (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 

    1. Go to  17).

    No 

    1. Repair the excessive resistance in the (K900) Sensor ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  11. 11) EXCESSIVE RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT 
    Fig 7: Checking MAP Sensor 5-Volt Supply Circuit
    GC0002635Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the MAP Sensor harness connector.

    Disconnect the C1 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 Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (F856) 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 

    1. Go to  12).

    No 

    1. Repair the excessive resistance in the (F856) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  12. 12) (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 8: Checking MAP Sensor 5-Volt Supply Circuit For Short To Ground
    GC0002636Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (F856) 5-volt Supply circuit in the MAP Sensor harness connector.

    Is the resistance above 100k ohms? 

    Yes 

    1. Go to  13).

    No 

    1. Repair the short to ground in the (F856) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  13. 13) MAP SENSOR 
    Fig 9: Identifying MAP Sensor Signal & Ground Circuit
    GC0002637Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Connect the C1 PCM harness connector.

    Ignition on, engine not running.

    With a scan tool, monitor the MAP Sensor voltage.

    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 

    1. Replace the MAP Sensor.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  14).
      NOTE: Remove the jumper wire before continuing.
  14. 14) EXCESSIVE RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT 
    Fig 10: Checking Excessive Resistance In MAP Signal Circuit
    GC0002638Courtesy of CHRYSLER LLC

    Turn the ignition off.

    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 Miller Special Tool #8815 to perform diagnosis.

    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 

    1. Go to  15).

    No 

    1. Repair the excessive resistance in the (K1) MAP Signal circuit
    2. Perform POWERTRAIN VERIFICATION TEST .
  15. 15) (K1) MAP SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 11: Checking MAP Sensor Signal Circuit For Short To Ground
    GC0002639Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (K1) MAP Signal circuit in the MAP Sensor harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (K1) MAP Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    Go to step  16).

  16. 16) EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT 
    Fig 12: Checking MAP Sensor Ground Circuit
    GC0002640Courtesy 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 (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 

    1. Go to  17).

    No 

    1. Repair the excessive resistance in the (K900) Sensor ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  17. 17) 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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