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Home >> Chrysler >> 2011 >> 300 C, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 419 (5.7L CNG - DTCS P2135 To U147B - 2500 Hd) >> Diagnosis And Testing >> P2172-High Airflow/Vacuum Leak Detected (Instantaneous Accumulation) >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2013 RAM 2500 HD and 2012 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.
  1. ACTIVE DTC 
    NOTE:

    The most likely cause of this DTC is a vacuum leak. Check for any TSBs before continuing.

    NOTE:

    The throttle plate should be free from binding and carbon build up.

    NOTE:

    Question the customer about weather conditions, as ice build up on the throttle blade can cause this fault when the ambient air temperature is in the -10°C (14°F) to 4°C (39°F) range.

    1. Turn the ignition on.
    2. With the scan tool, record and erase all DTCs.
    3. Start the engine and allow it to idle.
    4. With a scan tool, read the active DTCs.

      Is the DTC Active at this time?

      Yes 

      • Go To  2

      No 

  2. VACUUM LEAK INSPECTION 
    1. Turn the ignition off.
    2. Remove the Air Cleaner Assembly.
    3. Remove the Air Filter.
    4. Inspect the Throttle Body opening for signs of any foreign materials or excessive carbon build up.
    5. Thoroughly inspect the engine area for any vacuum leaks.

      Were any leaks found?

      Yes 

      • Repair the leaks as necessary.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  3
  3. CHECK FOR RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the MAP Sensor harness connector.
    3. Disconnect the PCM C2 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 the GPEC Diagnostic Adaptor to perform the diagnosis.

    4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    5. Measure the resistance of the (K1) MAP Signal circuit between the MAP Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the excessive resistance in the (K1) MAP Signal circuit
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  4. CHECK FOR RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT 
    1. Measure the resistance of the (K900) Sensor ground circuit between the MAP Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  5

      No 

      • Repair the excessive resistance in the (K900) Sensor ground circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  5. MAP SENSOR OPERATION 
    1. Reconnect the MAP Sensor and PCM C2 harness connectors.
    2. Perform the CHECKING THE MAP SENSOR OPERATION test procedure. Refer to DIAGNOSIS AND TESTING .

      Is the MAP Sensor operating properly?

      Yes 

      • Go To  6

      No 

      • Replace the MAP Sensor in accordance with the service information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  6. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor, Throttle Body, and the Powertrain Control Module (PCM).
    2. Look for any chafed, pierced, pinched, or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the MAP Sensor, Throttle Body, and Powertrain Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      • Repair as necessary.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No