P0072

P0072-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT LOW (TIPM)

P0072-Ambient Air Temperature Sensor Circuit Low (TIPM):

WHEN MONITORED
With the ignition on. Battery voltage greater than 10.4 volts.

SET CONDITION
The Ambient Air Temperature (AAT) sensor circuit voltage at the TIPM is less than 0.078 of a volt for more than 2.8 seconds. One Trip Fault. Three good trips to clear the MIL.

POSSIBLE CAUSES
- (G31) AAT signal circuit shorted to ground
- (G31) AAT signal circuit shorted to the (G931) AAT return
- AAT sensor
- TIPM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. AAT SENSOR VOLTAGE BELOW 0.078 OF A VOLT

Ignition on, engine not running.
With a scan tool, read the AAT voltage.

Q: Is the voltage below 0.078 of a volt?

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

2. AAT SENSOR

Turn the ignition off.
Disconnect the AAT harness connector.
Ignition on, engine not running.
With a scan tool, read AAT voltage.

Q: Is the voltage above 1.0 volt?

YES: Replace the AAT Sensor. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3




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

Turn the ignition off.
Disconnect the C4 TIPM harness connectors.
Measure the resistance between the (G931) AAT Return circuit and the (G31) AAT Signal circuit in the AAT Sensor harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Repair the short to between the (G931) AAT Return circuit and the (G31) AAT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4




4. (G31) AAT SIGNAL CIRCUIT SHORTED GROUND

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 5

5. 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 the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace and program the Totally Integrated Power Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test