P0073–AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH
For a complete wiring diagram Refer to Section 8W.
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When Monitored:
With the ignition on. Battery voltage greater than 10 volts.
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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.
Possible Causes
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(G31) AAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
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(G31) AAT SIGNAL CIRCUIT OPEN
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(G931) SENSOR GROUND CIRCUIT OPEN
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AMBIENT AIR TEMPERATURE SENSOR
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TOTALLY INTEGRATED POWER MODULE
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Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1.
AAT SENSOR VOLTAGE ABOVE 4.98 VOLTS
Ignition on, engine not running.
With a scan tool, read the Ambient Air Temperature Sensor voltage.
Is the voltage above 4.98 volts?
Yes
No
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
No
3.
(G31) AAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C4 TIPM 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
No
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 C4 TIPM harness connector.
Is the resistance below 5.0 ohms?
Yes
No
5.
(G931) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (G931) Sensor ground circuit from the AAT Sensor harness connector to the C4 TIPM harness connector.
Is the resistance below 5.0 ohms?
Yes
No
6.
TOTALLY INTEGRATED POWER MODULE
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.
Were there any problems found?
Yes
No