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P0073–AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH (CONTINUED) For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS). For a complete wiring diagram Refer to Section 8W. • When Monitored: • Set Condition: Possible Causes (G31) AAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE (G31) AAT SIGNAL CIRCUIT OPEN (G931) SENSOR GROUND CIRCUIT OPEN AMBIENT AIR TEMPERATURE SENSOR FRONT CONTROL MODULE Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - 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 >> Go To 2 No >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 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 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 >> Replace the Ambient Air Temperature Sensor. Perform the POWERTRAIN VERIFICATION TEST. (Refer No >> Go To 3 NOTE: Remove the jumper wire before continuing. HB ENGINE ELECTRICAL DIAGNOSTICS 9 - 71 |