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

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

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.
CHECK DTC.
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC P0087 displayed? (Current malfunction)

Yes : Go to 3.

No : Check the appropriate DTC using the "Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .
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.
CHECK FUEL PRESSURE.
1. Start the engine.
2. Using the Subaru Select Monitor, read the value in [Fuel Rail Pressure A] and [Commanded Fuel Rail Pressure A] when racing the engine.
  NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .
Is the value of [Fuel Rail Pressure A] synchronized with that of [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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>FUEL PRESSURE SENSOR .
CHECK OF FUEL PUMP.
1. Turn the ignition switch to ON. (Engine OFF)
2. Using the Subaru Select Monitor, select [Fuel Pump Relay] of [Active Test] to operate the fuel pump.
  NOTE: For detailed operation procedures, refer to the "Active Test". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>ACTIVE TEST .
Does the fuel pump emit operating sound?

Yes : Go to 6.

No : Check fuel pump circuit. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>DIAGNOSTICS WITH PHENOMENON>FUEL PUMP CIRCUIT .
CHECK FUEL PRESSURE (LOW PRESSURE SIDE).
Check the fuel pressure on low-pressure side. Ref. to MECHANICAL (H4DOTC)>FUEL PRESSURE>INSPECTION .

Is the check result OK?

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 .
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 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 "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .
Does the value of [Fuel Rail Pressure A] decrease rapidly?

Yes : Go to 8.

No : Go to 9.
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 check result OK?

Yes : Go to 9.

No : Replace the high-pressure fuel pump. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>HIGH PRESSURE FUEL PUMP .
CHECK FOR REPRODUCTION OF FAILURE.
1. Turn the ignition switch to ON.
2. Using the Subaru Select Monitor or a general scan tool, perform the clear memory of [Engine]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
3. Perform the corresponding inspection mode. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>INSPECTION MODE .
4. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC P0087 displayed? (Current malfunction)

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 "CHECK FOR FUEL DELIVERY LINE LEAKAGE (HIGH PRESSURE SIDE)" without replacing the high-pressure fuel pump. Go to 11.

No : End.
CHECK FOR REPRODUCTION OF FAILURE.
1. Using the Subaru Select Monitor or a general scan tool, perform the clear memory of [Engine]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
2. Perform the corresponding inspection mode. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>INSPECTION MODE .
3. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC P0087 displayed? (Current malfunction)

Yes : Go to 11.

No : End.
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 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 "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .
Does the value of [Fuel Rail Pressure A] decrease rapidly?

Yes : Replace the fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>FUEL INJECTOR .

No : Repair the poor contact of ECM connector.