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
  CAUTION: After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode>OPERATION . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode>PROCEDURE .

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.
   • 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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Fuel Delivery and Evaporation Lines . Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Fuel Injector .
   • No  : Go to 2. 
2. CHECK FOR ANY OTHER DTC ON DISPLAY. 

   Is any other DTC displayed?

   • Yes  : Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>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". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>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 fuel pressure and the value of [Target Fuel pressure gauge] when racing the engine.
      NOTE: For detailed procedures, refer to "Data Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Subaru Select Monitor .

   Is the value of fuel pressure synchronized with that of [Target Fuel pressure gauge]?

   • Yes  : Go to 5. 
   • No  :
     • The value in Fuel pressure gauge does not increase: Go to 7. 
     • The value in Fuel pressure gauge does not change: Replace the fuel pressure sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Fuel Pressure Sensor .
5. CHECK OF FUEL PUMP. 
   1. Turn the ignition switch to ON. (Engine OFF)
   2. From [Fuel Pump Control (ON/OFF Dr.)] of Active Test, check for the operating sound of the fuel pump when performing ON/OFF drive for the fuel pump.
      NOTE: For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".

   Does the fuel pump emit operating sound?

   • Yes  : Go to 6. 
   • No  : Check fuel pump circuit. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Diagnostics for Engine Starting Failure>FUEL PUMP CIRCUIT .
6. CHECK FUEL PRESSURE (LOW PRESSURE SIDE). 

   Check the fuel pressure on low-pressure side. Ref. to MECHANICAL(H4DOTC)>Fuel Pressure>INSPECTION .

   Is the fuel pressure normal?

   • Yes  : Go to 7. 
   • No  : Check the fuel pump and fuel delivery line. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Fuel Pump>INSPECTION . Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>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 values of Fuel pressure gauge 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 procedures, refer to "Data Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Subaru Select Monitor .

   Does the value in Fuel pressure gauge decrease rapidly?

   • Yes  : Go to 8. 
   • No  : Go to  9.
8. CHECK HIGH-PRESSURE FUEL PUMP. 

   Check the high-pressure fuel pump. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>High Pressure Fuel Pump>INSPECTION .

   Is the high-pressure fuel pump normal?

   • Yes  : Go to 9. 
   • No  : Replace the high-pressure fuel pump. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>High Pressure Fuel Pump .
9. CHECK FOR REPRODUCTION OF FAILURE. 
   1. Clear the memory. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode .
   2. Perform appropriate drive cycle test. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Drive Cycle .
   3. Read the DTC. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Read Diagnostic Trouble Code (DTC) .

   Is the same DTC as current diagnosis output?

   • Yes  : Replace the high-pressure fuel pump. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>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. Clear the memory. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode .
    2. Perform appropriate drive cycle test. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Drive Cycle .
    3. Read the DTC. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Read Diagnostic Trouble Code (DTC) .

    Is the same DTC as current diagnosis output?

    • 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 values of Fuel pressure gauge 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 procedures, refer to "Data Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Subaru Select Monitor .

    Does the value in Fuel pressure gauge decrease rapidly?

    • Yes  : Replace the fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Fuel Injector .
    • No  : Repair the poor contact of ECM connector.