P0072

P0072-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT LOW





For a complete wiring diagram refer to Diagrams/Electrical.


- When Monitored:

The ignition key on.

- Set Condition:

Ambient Temperature Sensor is less than 0.078 of a volt at the TIPM for 4.8 seconds. One Trip Fault. Three good trips to turn off the MIL.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.


Diagnostic Test


1. DTC IS ACTIVE

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.


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

With the scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition


2. CHECKING AAT SENSOR

Turn the ignition off.

Disconnect the Ambient Air Temperature Sensor harness connector.

Ignition on, engine not running.

With a scan tool, read the AAT Sensor 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

- Replace the Ambient Temperature Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3


3. (G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND





Turn the ignition off.

Disconnect the C4 TIPM harness connector.

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. Powertrain Verification Test

No

- Go To 4


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





Measure the resistance between the (G931) Sensor ground 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) Sensor ground circuit and the (G31) AAT Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5


5. EXCESSIVE RESISTANCE IN THE (G31) AAT SIGNAL CIRCUIT





Measure the resistance of the (G31) AAT Signal circuit between the Ambient Air Temperature Sensor harness connector and the C4 TIPM harness connector.

Is the resistance below 5.0 ohms?

Yes

- Go to 6

No

- Repair the excessive resistance in the (G31) AAT Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


6. TOTALLY INTEGRATED POWER MODULE

NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform BODY VERIFICATION TEST VER - 1. Body Verification Test

No

- Replace and program the Totally Integrated Power Module.
- Perform BODY VERIFICATION TEST VER - 1. Body Verification Test