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Home >> Jeep >> 2014 >> Wrangler Sahara, Standard Trans >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> 3.6L - DTCS P2135 To U1418 >> Diagnosis And Testing >> P2174-Low Airflow/Restriction Detected (Instantaneous Accumulation) >> Diagnostic Test

Diagnostic Test

  1. ACTIVE DIAGNOSTIC TROUBLE CODE (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, TP Sensor, Oxygen Sensor, Fuel related or MAP Sensor DTCs 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. Ignition on, engine not running.
    2. With a scan tool, read the 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.
    5. Check the intake tube and air cleaner for obstructions; include snow packing questions to customer.

      Were any restrictions found?

      Yes 

      No 

      • Go To  3
  3. MAP SENSOR OPERATION 
    1. Start the engine.
    2. With a scan tool, monitor the MAP Sensor voltage.
    3. Snap the Accelerator pedal.

      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  4

      No 

      • Go To  13
  4. TP SENSOR OPERATION 
    1. Ignition on, engine not running.
    2. With a scan tool, perform the Throttle Follower Test.
    3. TP Sensor No. 1 should start at approximately 0.7 of a Volt and increase to 4.3 Volts.
    4. TP Sensor No. 2 should start at approximately 4.3 Volts and decrease to 0.7 of a Volt.

      Is the voltage transition smooth between the appropriate values?

      Yes 

      No 

      • Go To  5
  5. 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.
      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 (F855) 5-Volt Supply circuit from the Throttle Body harness connector to the GPEC Adaptor.

      Is the resistance below 100 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the excessive resistance in the (F855) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 1: Checking 5-Volt Supply Circuit For Short To Ground
    GC0150106Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between ground and (F855) 5-Volt Supply circuit at the Throttle Body harness connector.

      Is the resistance above 100k Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the short to ground in the (F855) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. TP SENSOR 
    1. Connect the PCM C2 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 (K922) TP Sensor Return circuit in the Throttle Body harness connector.
    5. TP Sensor No. 1 voltage should start at approximately 4.7 Volts and decrease to 0.3 of a Volt.
    6. Connect a jumper wire between the (K122) TP Sensor No. 2 Signal circuit and the (F855) 5-Volt Supply circuit in the Throttle Body harness connector.
    7. TP Sensor No. 2 voltage should start at approximately 0.3 Volts and increase to 4.7 Volts.

      Does the TP Sensor voltage change to the appropriate voltage with the jumper wire 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 POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. RESISTANCE IN THE (K22) TP SENSOR NO. 1 SIGNAL CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
    3. Measure the resistance of the (K22) TP Sensor No. 1 Signal 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 (K22) TP Sensor No. 1 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  9. RESISTANCE IN THE (K122) TP SENSOR NO. 2 SIGNAL CIRCUIT 
    1. Measure the resistance of the (K122) TP 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 (K122) TP Sensor No. 2 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  10. (K22) TP SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking TP Sensor Signal Circuit For Short To Ground
    GC0150102Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between ground and the (K22) TP Sensor No. 1 Signal circuit at the Throttle Body harness connector.

      Is the resistance above 100k Ohms?

      Yes 

      • Go To  11

      No 

      • Repair the short to ground in the (K22) TP Sensor No. 1 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  11. (K122) TP SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 3: Checking TP Sensor No. 2 Signal Circuit For Short To Ground
    GC0150154Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between ground and the (K122) TP Sensor No. 2 Signal circuit at the Throttle Body harness connector.

      Is the resistance above 100k Ohms?

      Yes 

      • Go To  12

      No 

      • Repair the short to ground in the (K122) TP Sensor No. 2 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  12. RESISTANCE IN THE (K922) TP 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  19

      No 

      • Repair the excessive resistance in the (K922) TP Sensor Return circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  13. 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  14

      No 

      • Repair the excessive resistance in the (F856) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  14. (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 4: Checking MAP Sensor 5-Volt Supply Circuit For Short To Ground
    GC0101913Courtesy of CHRYSLER GROUP, LLC
    1. 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 

      • Go To  15

      No 

      • Repair the short to ground in the (F856) 5-Volt Supply circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  15. MAP SENSOR 
    Fig 5: Checking MAP Sensor Circuit
    GC0101914Courtesy of CHRYSLER GROUP, LLC
    1. Connect the PCM C2 harness connector.
    2. Ignition on, engine not running.
    3. With a scan tool, monitor the MAP Sensor voltage.
    4. Connect a jumper wire between the (K15) MAP Signal circuit and the (K900) Sensor ground circuit.
    5. Cycle the ignition switch from off to on.
    6. With a scan tool, monitor the MAP Sensor voltage.

      Does the scan tool display MAP voltage from approximately 4.9 Volts to below 0.5 Volt with the jumper wire installed?

      Yes 

      No 

      • Go To  16
        NOTE:

        Remove the jumper wire before continuing.

  16. RESISTANCE IN THE (K15) MAP SIGNAL CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the C2 PCM harness connector.
    3. Measure the resistance of the (K15) MAP Signal circuit from the MAP Sensor harness connector to the PCM C2 harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  17

      No 

      • Repair the excessive resistance in the (K15) MAP Signal circuit
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  17. (K15) MAP SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 6: Checking MAP Signal Circuit For Short To Ground
    GC0101910Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between ground and the (K15) MAP Signal circuit in the MAP Sensor harness connector.

      Is the resistance above 100k Ohms?

      Yes 

      • Go To  18

      No 

      • Repair the short to ground in the (K15) MAP Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  18. 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  19

      No 

      • Repair the excessive resistance in the (K900) Sensor ground circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  19. 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 

      No 

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