P0073

P0073-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH





For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:

The Ambient Temperature Sensor voltage is greater than 4.98 volts at the PCM for 2.8 seconds. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. ACTIVE DTC

Ignition on, engine not running.

With a 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. AAT SENSOR





Turn the ignition off.

Disconnect the Ambient Air Temperature Sensor harness connector.

Connect a jumper wire between the (G31) AAT Signal circuit and the (G931) Sensor ground circuit in the AAT Sensor harness connector.

Ignition on, engine not running.

With a scan tool, read AAT Sensor voltage.

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

Yes

- 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 BATTERY VOLTAGE





Turn the ignition off.

Disconnect the C2 FCM harness connector.

Ignition on, engine not running.

Measure the voltage on the (G31) AAT Signal circuit in the AAT Sensor harness connector.

Is the voltage above 0 volts?

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





Turn the ignition off.

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





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

NOTE: Before continuing, check the FCM 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. Body Verification Test

No

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