LEMON Manuals: Even more car manuals for everyone
Home >> Jeep >> 2007 >> Commander Base, 4.7 P, AWD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0016 To P0122, Pre-Diagnostic Troubleshooting Procedure, Intermittent Condition >> P0071-Ambient Air Temperature Sensor Performance >> Diagnostic Test

Diagnostic Test

  1. 1) ACTIVE DTC 
    NOTE: Diagnose any CAN - C Communication DTCs before continuing.

    Turn the ignition off.

    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).

    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.

    With a scan tool, select View DTCs.

    Is the DTC Active or Pending at this time? 

    Yes 

    1. Go to  3).

    No 

    1. Refer to INTERMITTENT CONDITION .
  2. 2) AMBIENT AIR TEMPERATURE 

    Turn the ignition off.

    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.

    Turn the ignition on.

    With a 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 

    1. Refer to INTERMITTENT CONDITION .

    No 

    1. Go to  3).
  3. 3) AAT SENSOR VOLTAGE 

    Turn the ignition off.

    Disconnect the AAT sensor harness connector.

    Ignition on, engine not running.

    With a scan tool, read the AAT voltage.

    NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus .1 volt) with the connector disconnected.

    Does the scan tool display the voltage as described above? 

    Yes 

    1. Go to  4).

    No 

    1. Go to  5).
  4. 4) AAT SENSOR 
    Fig 1: Identifying Ambient Air Temperature Sensor Connector Terminals
    GC0002646Courtesy of CHRYSLER LLC

    Connect a jumper wire between the (G31) AAT Signal circuit and the (G931) Sensor Ground circuit in the Ambient Air Temperature Sensor harness connector.

    With a scan tool, read the Ambient Air Temperature Sensor voltage.

    NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus .1 volt) with the jumper wire in place.

    Does the scan tool display the voltage as described above? 

    Yes 

    1. Verify that there is good pin to terminal contact in the Ambient Air Temperature Sensor and Front Control Module connectors. If OK, replace the AAT Sensor.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  5).
      NOTE: Remove the jumper wire before continuing.
  5. 5) (G31) AAT SIGNAL CIRCUIT HIGH RESISTANCE 

    Turn the ignition off.

    Reconnect the AAT sensor harness connector.

    Using a voltmeter perform a voltage drop test. Backprobe the (G31) AAT Signal circuit at the AAT Sensor harness connector and the C2 FCM 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 can result in personal injury or death.

    Start the engine and allow it to reach normal operating temperature.

    Monitor the voltmeter.

    Is the voltage below 0.5 volts? 

    Yes 

    1. Go to  6).

    No 

    1. Repair the high resistance in the (G31) AAT Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. 6) (G931) SENSOR GROUND CIRCUIT HIGH RESISTANCE 

    Turn the ignition off.

    Using a voltmeter perform a voltage drop test. Backprobe the (G931) Sensor ground circuit at the AAT Sensor harness connector and the C2 FCM 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 can result in personal injury or death.

    Start the engine and allow it to reach normal operating temperature.

    Monitor the voltmeter.

    Is the voltage below 0.5 volts? 

    Yes 

    1. Go to  7).

    No 

    1. Repair the high resistance in the (G931) Sensor ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  7. 7) FRONT CONTROL MODULE (FCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the AAT Sensor and the Front Control Module (FCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Sensor and Front Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform BODY VERIFICATION TEST .

    No 

    1. Replace the Front Control Module per Service Information.
    2. Perform BODY VERIFICATION TEST .
scientia non olet · About LEMON Manuals