P0073

P0073-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH





For a complete wiring diagram Refer to the Wiring Information.

- When Monitored:
With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:
The Ambient Temperature Sensor voltage is greater than maximum acceptable value. 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. ACTIVE DTC
1. 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 possible serious or fatal injury.

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

2. 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 Test.

2. AAT SENSOR




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

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

Yes

- Verify that there is good pin to terminal contact in the AAT Sensor and Front Control Module connectors. If OK, replace the Ambient Air Temperature 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 VOLTAGE




1. Turn the ignition off.
2. Disconnect the C2 FCM 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. 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 from the AAT Sensor harness connector to the C2 FCM 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) SENSOR GROUND CIRCUIT OPEN




1. Measure the resistance of the (G931) Sensor ground circuit from the AAT Sensor harness connector to the C2 FCM harness connector.

Is the resistance below 5.0 ohms?

Yes

- Go To 6

No

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

6. FRONT CONTROL MODULE (FCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the AAT Sensor and the Front Control Module (FCM).
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 AAT Sensor and Front Control Module connectors.
4. Search for any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

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

No

- Replace the Front Control Module.
- Perform BODY VERIFICATION TEST. Body Verification Test.