DTC P0068: Map/MAF - Throttle Position Correlation: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

1. CHECK AIR INTAKE SYSTEM  .

   Check the air intake system.

   Are there holes, loose bolts or disconnection of hose on air intake system?

   Yes:  Repair the air intake system.

   No:  Go to  2

2. CHECK MANIFOLD ABSOLUTE PRESSURE SENSOR  .
   1. Start the engine and warm up engine until coolant temperature is higher than 75°C (167°F).
   2. Place the gear shift lever in the neutral position.
   3. Turn the A/C switch to OFF.
   4. Turn all the accessory switches to OFF.
   5. Read the value of «Mani. Absolute Pressure» using the Subaru Select Monitor or a general scan tool.
      NOTE:

      • Subaru Select Monitor

        For detailed operation procedures, refer to "Current Data Display For Engine". Ref. to ENGINE (DIAGNOSTICS) (STI)>Subaru Select Monitor .

      • General scan tool

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

   Is the value in «Mani. Absolute Pressure» 73.3 - 106.6 kPa (550 - 800 mmHg, 21.65 - 31.5 inHg) when the ignition is turned ON, and 20 - 46.7 kPa (150 - 350 mmHg, 5.91 - 13.78 inHg) during idling?

   Yes:  Go to  3

   No:  Replace the manifold absolute pressure sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (STI)>Manifold Absolute Pressure Sensor .

3. CHECK THROTTLE OPENING ANGLE  .

   Using the Subaru Select Monitor or a general scan tool, read the value in «Throttle Opening Angle».

   NOTE:

   • Subaru Select Monitor

     For detailed operation procedures, refer to "Current Data Display For Engine". Ref. to ENGINE (DIAGNOSTICS) (STI)>Subaru Select Monitor .

   • General scan tool

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

   Is the value in «Throttle Opening Angle» with the throttle fully closed less than 5%?

   Yes:  Go to  4

   No:  Replace the electronic throttle control. Ref. to FUEL INJECTION (FUEL SYSTEMS) (STI)>Throttle Body .

4. CHECK THROTTLE OPENING ANGLE  .

   Read «Throttle Opening Angle» under the engine current data display using Subaru Select Monitor.

   Is the value in «Throttle Opening Angle» with the throttle fully open 85% or more?

   Yes:  Replace the manifold absolute pressure sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (STI)>Manifold Absolute Pressure Sensor .

   No:  Replace the electronic throttle control. Ref. to FUEL INJECTION (FUEL SYSTEMS) (STI)>Throttle Body .