DTC P0087: Fuel Rail/System Pressure - Too Low Bank 1: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Improper idling
• Poor driving performance
• Poor acceleration

1. CHECK FOR FUEL DELIVERY LINE LEAKAGE. 

   Visually check the fuel delivery line for leakage.

   WARNING:

   • When checking fuel delivery line during engine operation, be very careful so that one's hair, body and clothes do not touch the rotating part in the engine compartment.
   • If there is fuel leakage, the fuel can be combusted spontaneously by the engine heat, resulting in serious accident. Therefore, take extra care of possible fuel leakage.
   • Prepare the necessary fire-extinguishing appliance for immediate fire fighting in case of fire.
   NOTE: Concerning the section where visible inspection is difficult, the fuel odor provides a good indication of determining the fuel leakage.

   Are there leaks from the fuel delivery line?

   Yes:  Replace the faulty fuel delivery line. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>FUEL DELIVERY AND EVAPORATION LINES . Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>FUEL INJECTOR .

   No:  Go to  2.

2. 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 P0087 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  3.

3. CHECK EXPERIENCE OF RUNNING OUT OF FUEL. 

   Check if there was an experience of running out of fuel using "Check List for Interview". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>CHECK LIST FOR INTERVIEW>CHECK>CHECK LIST NO. 2 .

   Has the vehicle experienced running out of fuel?

   Yes:  Finish the diagnosis.

   NOTE: DTC may be stored by running out of fuel.

   No:  Go to  4.

4. CHECK FUEL PRESSURE. 
   1. Start the engine.
   2. Using the Subaru Select Monitor, read the values in «Fuel Rail Pressure A» and «Commanded Fuel Rail Pressure A» when racing the engine.
      NOTE: For detailed operation procedures, refer to "Current Data Display For Engine". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>SUBARU SELECT MONITOR .

   Is the value in «Fuel Rail Pressure A» synchronized with the one in «Commanded Fuel Rail Pressure A»?

   Yes:  Go to  5.

   No

   • The value in «Fuel Rail Pressure A» does not increase: Go to  7.
   • The value in «Fuel Rail Pressure A» does not change: Replace the fuel pressure sensor. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>FUEL PRESSURE SENSOR .
5. CHECK OF FUEL PUMP. 
   1. Turn the ignition switch to ON. (Engine OFF)
   2. On the «Active Test» item, select «Fuel Pump Relay», and perform ON/OFF drive operation.
      NOTE: For detailed operation procedures, refer to the "Active Test". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>ACTIVE TEST .
   3. Check for operating sound in the fuel pump according to ON/OFF switching operation.

   Does the fuel pump emit operating sound?

   Yes:  Go to  6.

   No:  Check fuel pump circuit. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>DIAGNOSTICS FOR ENGINE STARTING FAILURE>FUEL PUMP CIRCUIT .

6. CHECK FUEL PRESSURE (LOW PRESSURE SIDE). 

   Check the fuel pressure on low-pressure side. Refer to MECHANICAL (EXCEPT FOR STI)>FUEL PRESSURE>INSPECTION .

   Is the check result OK?

   Yes:  Go to  7.

   No:  Check the fuel pump and fuel delivery line. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>FUEL PUMP>INSPECTION . Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>FUEL DELIVERY AND EVAPORATION LINES>INSPECTION .

7. CHECK FOR FUEL DELIVERY LINE LEAKAGE (HIGH PRESSURE SIDE). 
   1. Start the engine.
   2. Using the Subaru Select Monitor, read the change in value of «Fuel Rail Pressure A» when stopping the engine.
   NOTE:

   • In order to maintain the communication with Subaru Select Monitor, turn the ignition switch to OFF, and immediately turn it to ON.
   • For detailed operation procedures, refer to "Current Data Display For Engine". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>SUBARU SELECT MONITOR .

   Does the value of «Fuel Rail Pressure A» decrease rapidly?

   Yes:  Go to  8.

   No:  Go to  9.

8. CHECK HIGH-PRESSURE FUEL PUMP. 

   Check the high-pressure fuel pump. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>HIGH PRESSURE FUEL PUMP>INSPECTION .

   Is the check result OK?

   Yes:  Go to  9.

   No:  Replace the high-pressure fuel pump. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>HIGH PRESSURE FUEL PUMP .

9. CHECK FOR REPRODUCTION OF FAILURE. 
   1. Perform the Clear Memory Mode. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>CLEAR MEMORY MODE .
   2. Perform appropriate drive cycle test. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>DRIVE CYCLE .
   3. Read the DTC. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC P0087 displayed?

   Yes:  Replace the high-pressure fuel pump. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>HIGH PRESSURE FUEL PUMP . After replacement, go to the next step. Go to  10.

   NOTE: When the high-pressure fuel pump has been replaced in step 8, go to the next step without replacing the high-pressure fuel pump. Go to  11.

   No:  End.

10. CHECK FOR REPRODUCTION OF FAILURE. 
    1. Perform the Clear Memory Mode. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>CLEAR MEMORY MODE .
    2. Perform appropriate drive cycle test. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>DRIVE CYCLE .
    3. Read the DTC. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

    Is DTC P0087 displayed?

    Yes:  Go to  11.

    No:  End.

11. CHECK FOR FUEL DELIVERY LINE LEAKAGE (HIGH PRESSURE SIDE). 
    1. Start the engine.
    2. Using the Subaru Select Monitor, read the change in value of «Fuel Rail Pressure A» when stopping the engine.
    NOTE:

    • In order to maintain the communication with Subaru Select Monitor, turn the ignition switch to OFF, and immediately turn it to ON.
    • For detailed operation procedures, refer to "Current Data Display For Engine". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>SUBARU SELECT MONITOR .

    Does the value of «Fuel Rail Pressure A» decrease rapidly?

    Yes:  Replace the fuel injector. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>FUEL INJECTOR .

    No:  Repair the poor contact of ECM connector.