GPEC

P0072-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT LOW





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:
The PCM detects that the Ambient Air Temperature Sensor input voltage is below the minimum acceptable value.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE

NOTE: Diagnose any CAN - C Communication DTCs before continuing.

NOTE: Diagnose and repair any system voltage DTCs before continuing with this test.

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 can result in personal injury or death.

With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go to 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking For An Intermittent DTC

2. (G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Disconnect the Ambient Air Temperature Sensor connector.
Disconnect the Totally Integrated Power Module (TIPM) connector.
Measure the resistance between ground and the (G31) AAT Signal circuit in the Ambient Air Temperature Sensor harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 3

No

- Repair the (G31) AAT Signal circuit for a short to ground.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

3. (G31) AAT SIGNAL CIRCUIT SHORTED TO (G931) AAT SENSOR GROUND CIRCUIT




Measure the resistance between the (G31) AAT Signal circuit and the (G931) AAT Sensor Ground circuit in the Ambient Air Temperature Sensor harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 4

No

- Repair the (G31) AAT Signal circuit for a short to the (G931) AAT Sensor Ground circuit.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

4. (G31) AAT SIGNAL CIRCUIT OPEN CIRCUIT OR HIGH RESISTANCE




Measure the resistance of the (G31) AAT Signal circuit between the Ambient Air Temperature Sensor harness connector and the Totally Integrated Power Module (TIPM) harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go to 5

No

- Repair the (G31) AAT Signal circuit for an open circuit or high resistance.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

5. AMBIENT AIR TEMPERATURE SENSOR SIGNAL CIRCUIT VOLTAGE
Turn the ignition off.
Connect the Totally Integrated Power Module (TIPM) connector.
Turn the ignition on.
With the scan tool, read the Ambient Air Temperature Sensor signal voltage.
Is the voltage above 4.5 volts with the Ambient Air Temperature Sensor harness disconnected?

Yes

- Go to 6

No

- Go to 7

6. AMBIENT AIR TEMPERATURE SENSOR
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ambient Air Temperature Sensor and the Totally Integrated Power Module (TIPM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

No

- Replace the Totally Integrated Power Module (TIPM).
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

7. TOTALLY INTEGRATED POWER MODULE (TIPM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ambient Air Temperature Sensor and the Totally Integrated Power Module (TIPM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.

No

- Replace and program the Totally Integrated Power Module (TIPM).
- Perform the PCM Verification Test Ver. 1Powertrain Verification Test.