Powertrain Control Module (PCM)

P0073-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH







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

- Set Condition:
The Ambient Air Temperature (AAT) sensor circuit voltage at the TIPM is greater than 4.98 volts for more than 2.8 seconds. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. AAT SENSOR VOLTAGE ABOVE 4.98 VOLTS
1. Ignition on, engine not running.
2. With a scan tool, read the AAT voltage.

Is the voltage above 4.98 volts?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. AAT SENSOR




1. Turn the ignition off.
2. Disconnect the AAT harness connector.
3. Connect a jumper wire between the (G31) AAT Signal circuit and the (G931) AAT Return circuit in the AAT harness connector.
4. Ignition on, engine not running.
5. With a scan tool, read AAT voltage.

Is the voltage below 1.0 volt with the jumper wire installed?

Yes

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

No

- Go To 3 NOTE: Remove the jumper wire before continuing.


3. (G31) AAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE




1. Turn the ignition off.
2. Disconnect the C4 TIPM harness connectors.
3. Ignition on, engine not running.
4. Measure the voltage on the (G31) AAT Signal circuit in the AAT Sensor harness connector.

Is voltage present?

Yes

- Repair the short to battery voltage in the (G31) AAT Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. (G31) AAT SIGNAL CIRCUIT OPEN




1. Turn the ignition off.
2. Measure the resistance of the (G31) AAT Signal circuit between he AAT Sensor harness connector and C4 TIPM harness connector.

Is the resistance below 5.0 ohms?

Yes

- Go To 5

No

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

5. (G931) AAT RETURN CIRCUIT OPEN




1. Measure the resistance of the (G931) AAT Return circuit between the AAT Sensor harness connector and the C4 TIPM harness connector.

Is the resistance below 5.0 ohms?

Yes

- Go To 6

No

- Repair the open in the (G931) AAT Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. TIPM

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

1. 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 the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

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