P0071

P0071-AMBIENT AIR TEMPERATURE SENSOR PERFORMANCE

P0071-Ambient Air Temperature Sensor Performance:

WHEN MONITORED
Engine off time is greater than 480 minutes. Ambient temperature is greater than 4° C (38° F).

SET CONDITION
After a calibrated amount of cool down time, the PCM compares the ECT Sensor, IAT Sensor and the Ambient Air Temperature Sensor values. If the Ambient Air Temperature Sensor value is not within a calibrated temperature amount of the other two temperature sensors an error is detected. Two 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
- (G931) Sensor ground circuit open
- (G31) AAT signal circuit shorted to ground
- (G31) AAT signal circuit shorted to the (G931) sensor ground circuit
- Ambient air temperature sensor
- TIPM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. ACTIVE DTC

NOTE: Diagnose any CAN - C Communication DTCs before continuing.

Ignition on, engine not running.
With a scan tool, read DTCs.

Q: Is the DTC active at this time?

YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




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

Turn the ignition off.
Disconnect the C4 TIPM harness connector.
Disconnect the AAT Sensor harness connector.

NOTE: Visually inspect both the component and the TIPM connectors. Look for damaged, partially broken wires, and backed out or corroded terminals.

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

3. AAT SENSOR VOLTAGE ABOVE 4.6 VOLTS

Turn the ignition off.
Connect the C4 TIPM harness connectors.
Ignition on, engine not running.
With a scan tool, read the AAT voltage.

Q: Is the voltage above 4.6 volts?

YES: Go To 4
NO: Go To 7




4. AAT SENSOR

Connect a jumper wire between the (G31) AAT Signal circuit and the (G931) AAT Return circuit in the AAT Sensor harness connector.
With a scan tool, read the AAT voltage.

Q: 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 5

NOTE: Remove the jumper wire before continuing.




5. (G31) AAT SIGNAL CIRCUIT OPEN

Turn the ignition off.
Disconnect the C4 TIPM harness connector.
Measure the resistance of the (G31) AAT Signal circuit from the AAT Sensor harness connector to the C4 TIPM harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 6
NO: Repair the open in the (G31) AAT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




6. (G931) AAT RETURN CIRCUIT OPEN

Measure the resistance of the (G931) AAT Return circuit from the AAT Sensor harness connector to the C4 TIPM harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 9
NO: Repair the open in the (G931) Sensor ground circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




7. (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.

Q: 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 8




8. (G31) AAT SIGNAL SHORTED TO THE (G931) AAT RETURN CIRCUIT

Measure the resistance between the (G31) AAT Signal circuit and the (G931) AAT Return circuit in the AAT Sensor harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Repair the short between the (G931) AAT Return circuit and the (G31) AAT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 9

9. TIPM

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.

Q: Were there any problems found?

YES: Repair as necessary. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test
NO: Replace the Totally Integrated Power Module. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test