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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 >> P0071-Ambient Air Temperature Sensor Performance >> Diagnostic Test

Diagnostic Test

  1. ACTIVE DTC 
    NOTE:

    Diagnose any CAN - C Communication DTCs before continuing.

    1. Turn the ignition off.
    2. If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -7° C (19.4° F).
    3. Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
    4. With the scan tool, select View DTCs.

      Is the DTC Active or Pending at this time?

      Yes 

      • Go To  3

      No 

      • Go To  2
  2. AMBIENT AIR TEMPERATURE 
    1. Turn the ignition off.
    2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -7° C (19.4° F) until the engine coolant temperature is equal to ambient temperature.
    3. Turn the ignition on.
    4. With the scan tool, compare the AAT, ECT and IAT sensor values.

      Is the Ambient Air Temperature Sensor value within 10° C (18° F) of the other two sensor values?

      Yes 

      No 

      • Go To  3
  3. AAT SENSOR VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the AAT sensor harness connector.
    3. Ignition on, engine not running.
    4. With the scan tool, read the AAT voltage.
      NOTE:

      The sensor voltage should be approximately 5.0 Volts (plus or minus 0.1 of a Volt) with the connector disconnected.

      Does the scan tool display the voltage as described above?

      Yes 

      • Go To  4

      No 

      • Go To  5
  4. AAT SENSOR 
    Fig 1: Checking AAT Sensor Signal Circuit
    GC0090641Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Connect a jumper wire between the (G31) AAT Signal circuit and the (G931) AAT Return circuit in the Ambient Air Temperature Sensor harness connector.
    3. Turn the ignition on.
    4. With the scan tool, read the Ambient Air Temperature Sensor voltage.
      NOTE:

      The sensor voltage should be approximately 0.0 Volts (plus or minus 0.1 of a Volt) with the jumper wire in place.

      Does the scan tool display the voltage as described above?

      Yes 

      No 

      • Go To  5
        NOTE:

        Remove the jumper wire before continuing.

  5. (G31) AAT SIGNAL CIRCUIT HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Reconnect the AAT sensor harness connector.
    3. Using a Voltmeter perform a voltage drop test. Backprobe the (G31) AAT Signal circuit at the AAT sensor harness connector and the C5 TIPM harness connector.
    4. Start the engine and allow it to reach normal operating temperature.
    5. Monitor the Voltmeter.

      Is the voltage below 0.5 of a Volt?

      Yes 

      • Go To  6

      No 

      • Repair the excessive resistance in the (G31) AAT Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. (G931) AAT RETURN CIRCUIT HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Using a Voltmeter perform a voltage drop test. Backprobe the (G931) AAT Return circuit at the AAT sensor harness connector and the C5 TIPM harness connector.
      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.

    3. Start the engine and allow it to reach normal operating temperature.
    4. Monitor the Voltmeter.

      Is the voltage below 0.5 of a Volt?

      Yes 

      • Go To  7

      No 

      • Repair the excessive resistance in the (G931) AAT Return circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. (G31) AAT SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 2: Checking AAT Signal Circuit For Short To Voltage
    GC0090642Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the C4 TIPM harness connector.
    3. Ignition on, engine not running.
    4. Measure the voltage on the (G31) AAT Signal circuit in the AAT Sensor harness connector.

      Is there any voltage present?

      Yes 

      • Repair the short to voltage in the (G31) AAT Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. (G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 3: Checking AAT Signal Circuit For Short To Ground
    GC0090643Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Measure the resistance between ground and the (G31) AAT Signal circuit in the AAT Sensor harness connector.

      Is the resistance below 100 Ohms?

      Yes 

      • Repair the short to ground in the (G31) AAT Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  9
  9. (G31) AAT SIGNAL CIRCUIT SHORTED TO THE (G931) AAT RETURN CIRCUIT 
    Fig 4: Checking AAT Signal Circuit For Short To AAT Return Circuit
    GC0090644Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between the (G931) AAT return circuit and the (G31) AAT Signal circuit in the AAT Sensor harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Repair the short between the (G931) AAT return circuit and the (G31) AAT Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  10
  10. TOTALLY INTEGRATED POWER MODULE 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the AAT Sensor and the Totally Integrated Power Module (TIPM).
    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 Sensor and Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      No