P0071-AMBIENT AIR TEMPERATURE SENSOR PERFORMANCE

For a complete wiring diagram Refer to Section 8W

When Monitored:
With engine off time greater than 480 minutes and ambient temperature greater than – 7° C (19.4° F).
Set Condition:
After a calibrated amount of cool down time, the PCM compares the AAT, ECT, and IAT Sensor values. If one sensor value is not within 10° C (18° F) of the other temperature sensors for two consecutive trips, a DTC will set. Three good trips to turn off the MIL.

Possible Causes

INTERMITTENT DTC

(G31) AAT SIGNAL CIRCUIT SHORTED TO VOLTAGE

(G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND

(G31) AAT SIGNAL CIRCUIT SHORTED TO (G931) AAT SENSOR GROUND CIRCUIT

(G31) AAT SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

(G931) AAT SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE

AMBIENT AIR TEMPERATURE SENSOR

TOTALLY INTEGRATED POWER MODULE (TIPM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Diagnostic Test

1.DTC IS ACTIVE

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

Is the status Active or Pending for this DTC?

Yes

Go to 3

Go to 2

2.AMBIENT AIR TEMPERATURE

Is the Ambient Air Temperature Sensor value within 10° C (18° F) of the other two sensor values?

Yes

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Go to 3

3.(G31) AAT SIGNAL CIRCUIT SHORTED TO VOLTAGE

Is there any voltage present?

Yes

Repair the (G31) AAT Signal circuit for a short to voltage.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 4

4.(G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND

Is the resistance above 100 ohms?

Yes

Go to 5

Repair the (G31) AAT Signal circuit for a short to ground.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

5.(G31) AAT SIGNAL CIRCUIT SHORTED TO (G931) AAT SENSOR GROUND CIRCUIT

Is the resistance above 100 ohms?

Yes

Go to 6

Repair the (G31) AAT Signal circuit for a short to the (G931) AAT Sensor Ground circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

6.(G31) AAT SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Is the resistance below 5.0 ohms?

Yes

Go to 7

Repair the (G31) AAT Signal circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

7.(G931) AAT SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Is the resistance below 5.0 ohms?

Yes

Go to 8

Repair the (G931) AAT Sensor Ground for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

8.AMBIENT AIR TEMPERATURE SENSOR

Is the voltage below 1.0 volt with the jumper wire in place?

Yes

Replace the Ambient Air Temperature Sensor in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 9

9.TOTALLY INTEGRATED POWER MODULE (TIPM)

Were any problems found?

Yes

Repair as necessary.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace the Totally Integrated Power Module (TIPM) in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).