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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 419 (5.7L CNG - DTCS P2135 To U147B - 2500 Hd) >> Diagnosis And Testing >> P2174-Low Airflow/Restriction 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 plugged intake air system or dirty Throttle Body. Check for any TSBs before continuing.

    NOTE:

    Diagnose any 5-Volt Supply, TPS, Oxygen Sensor, Fuel related or MAP Sensor DTCs before continuing.

    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 active DTCs.

      Is the DTC Active at this time?

      Yes 

      • Go To  2

      No 

  2. RESTRICTED AIR INLET SYSTEM 
    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. Check the intake tube and air cleaner for obstructions; include snow packing questions to customer.

      Were any restrictions found?

      Yes 

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

      No 

      • Go To  3
  3. CHECK FOR EXCESSIVE RESISTANCE IN THE (F856) 5-VOLT SUPPLY 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 (F856) 5-Volt Supply circuit from the MAP Sensor harness connector to the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the excessive resistance in the (F856) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  4. CHECK FOR EXCESSIVE RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT 
    1. Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  5

      No 

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

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the excessive resistance in the (K900) Sensor ground circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  6. 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  7

      No 

      • Replace the MAP Sensor in accordance with the service information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  7. THROTTLE POSITION SENSOR OPERATION 
    1. Ignition on, engine not running.
    2. With a scan tool, perform the Throttle Follower Test.
    3. TPS 1 should start at approximately 0.7 volts and increase to 4.3 volts.
    4. TPS 2 should start at approximately 4.3 volts and decrease to 0.7 volts.

      Is the voltage transition smooth between the appropriate values?

      Yes 

      No 

      • Go To  8
  8. CHECK FOR EXCESSIVE RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the Throttle Body harness connector.
    3. Disconnect the PCM C2 harness connector.
    4. Measure the resistance of the (F855) 5-Volt Supply circuit from the Throttle Body harness connector to the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  9

      No 

      • Repair the excessive resistance in the (F855) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  9. CHECK FOR EXCESSIVE RESISTANCE IN THE (K22) TPS 1 SIGNAL CIRCUIT 
    1. Measure the resistance of the (K22) TPS 1 Signal circuit from the Throttle Body harness connector to the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  10

      No 

      • Repair the excessive resistance in the (K22) TPS 1 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  10. CHECK FOR EXCESSIVE RESISTANCE IN THE (K122) TPS 2 SIGNAL CIRCUIT 
    1. Measure the resistance of the (K122) TPS Signal circuit from the Throttle Body harness connector to the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  11

      No 

      • Repair the excessive resistance in the (K122) TPS 2 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  11. CHECK FOR EXCESSIVE RESISTANCE IN THE (K922) TPS SENSOR RETURN CIRCUIT 
    1. Measure the resistance of the (K922) TP Sensor Return circuit from the Throttle Body harness connector to the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  12

      No 

      • Repair the excessive resistance in the (K922) TPS Return circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  12. THROTTLE POSITION SENSOR 
    1. Connect the PCM harness connector.
    2. Ignition on, engine not running.
    3. With a scan tool, monitor the TPS voltage.
    4. Connect a jumper between the (K22) TPS 1 Signal circuit and the (K922) TPS Return circuit at the Throttle Body harness connector.
    5. TPS 1 voltage should start at approximately 4.7 volts and decrease to 0.3 volts.
    6. Connect a jumper between the (K122) TPS 2 Signal circuit and the (F855) 5-Volt Supply circuit at the Throttle Body harness connector.
    7. TPS 2 voltage should start at approximately 0.3 volts and increase to 4.7 volts.

      Do the TPS voltages change to the appropriate voltage with the jumper installed?

      Yes 

      • Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. Disconnect the Battery before replacing the Throttle Body Assembly. If OK, replace the Throttle Body Assembly. Refer to THROTTLE BODY, REMOVAL . After installation is complete, use a scan tool and select the ETC RELEARN function.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  13
  13. 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 

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