DTC P0071: Ambient Air Temperature Sensor Circuit "A" Range/Performance: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

1. CHECK DTC. 

   Read the engine DTC using the Subaru Select Monitor or general scan tool. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC other than P0071 displayed? (Current malfunction)

   Yes:  Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>LIST OF DIAGNOSTIC TROUBLE CODE (DTC) .

   No:  Go to  2.

2. CHECK CURRENT DATA. 
   1. Turn the ignition switch to ON.
   2. Read the value of «Ambient Air Temperature» using the Subaru Select Monitor or a general scan tool.
      NOTE:

      • Subaru Select Monitor

        For detailed operation procedures, refer to "Current Data Display For HVAC System". Refer to HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)>READ CURRENT DATA .

      • General scan tool

        For detailed operation procedures, refer to the general scan tool operation instructions.

   3. Read the change of the value in «Ambient Air Temperature» while heating and cooling the ambient sensor using a hair dryer.
   CAUTION: Do not heat the part to the temperature where you cannot touch it with your bare hand in order to prevent burning yourself and protect the part.

   Does the value of «Ambient Air Temperature» change between heating and cooling?

   Yes:  Repair the poor contact of ECM connector.

   No:  Replace the ambient sensor. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>AMBIENT SENSOR .