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Home >> Jeep >> 2014 >> Wrangler Sahara, Standard Trans >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> 3.6L - DTCS P000A To P0155 >> Diagnosis And Testing >> P0112-Intake Air Temperature Sensor 1 Circuit Low >> Diagnostic Test

Diagnostic Test

  1. DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE 
    1. Start the engine and allow it to reach normal operating temperature.
      WARNING:

      When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    2. Using the scan tool, select View DTCs.

      Is the status Active for this DTC?

      Yes 

      • Go To  2

      No 

  2. CHECK THE (K21) IAT SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    Fig 1: Checking IAT Signal Circuit For Short To Ground
    GC0150369Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the Intake Air Temperature Sensor harness connector.
    3. Disconnect the PCM C2 harness connector.
    4. Measure the resistance between ground and the (K21) IAT Signal circuit in the Intake Air Temperature Sensor harness connector.

      Is the resistance above 10k Ohms?

      Yes 

      • Go To  3

      No 

      • Repair the (K21) IAT Signal circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  3. CHECK FOR THE (K21) IAT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT 
    Fig 2: Checking IAT Signal Circuit For Short To Sensor Ground Circuit
    GC0150370Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between the (K21) IAT Signal circuit and the (K900) Sensor Ground circuit in the IAT Sensor harness connector.

      Is the resistance above 10k Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the (K21) IAT Signal circuit for a short to the (K900) Sensor Ground circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. CHECK THE (K21) IAT SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    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.

    1. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    2. Measure the resistance of the (K21) IAT Signal circuit between the IAT Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  5

      No 

      • Repair the (K21) IAT Signal circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. INTAKE AIR TEMPERATURE SENSOR 
    1. Turn the ignition off.
    2. Connect the PCM C2 harness connectors.
    3. Turn the ignition on.
    4. Using the scan tool, read the IAT Sensor signal voltage.

      Is the voltage above 4.5 Volts with the Intake Air Temperature Sensor harness disconnected?

      Yes 

      No 

      • Go To  6
  6. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Intake Air Temperature Sensor 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.
    4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
    5. Look for the data to change or for the DTC to reset during the wiggle test.
    6. Perform any Technical Service Bulletins that may apply.

      Were any problems found?

      Yes 

      No