P0073
P0073-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGHP0073 - Ambient Air Temperature Sensor Circuit High:
WHEN MONITORED
With the ignition on. Battery voltage greater than 10 volts.
SET CONDITION
The Ambient Temperature Sensor voltage is greater than 4.94 volts at the PCM for 4.8 seconds. One Trip Fault. Three good trips to turn off the MIL.
POSSIBLE CAUSES
- (G31) AAT signal circuit shorted to battery voltage
- (G31) AAT signal circuit open
- (K300) sensor ground circuit open
- Ambient air temperature sensor
- CAN C BUS circuit open or shorted
- BCM
- PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
DIAGNOSTIC TEST
1. AAT SENSOR VOLTAGE ABOVE 4.94 volts
NOTE: Diagnose any CAN C Bus Communication DTCs before continuing.
Ignition on, engine not running.
With a scan tool, read the Ambient Air Temperature Sensor voltage.
Q: Is the voltage above 4.94 volts?
YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
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 (K300) Sensor ground circuit in the AAT Sensor harness connector.
Ignition on, engine not running.
With a scan tool, read AAT Sensor voltage.
Q: 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 BCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (G31) AAT Signal circuit in the AAT Sensor harness connector.
Q: Is the voltage above 5.2 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 BCM harness connector.
Q: 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. (K300) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K300) Sensor ground circuit from the AAT Sensor harness connector to the C2 BCM harness connector.
Q: Is the resistance below 5.0 ohms?
YES: Go To 6
NO: Repair the open in the (K300) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
6. BCM
NOTE: Before continuing, check the BCM 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.
Q: Were there any problems found?
YES: Repair as necessary.
Perform the BODY VERIFICATION TEST. Body Verification Test
NO: Replace the Body Control Module.
Perform the BODY VERIFICATION TEST. Body Verification Test