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 Mode Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Clear Memory Mode>OPERATION , and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Inspection Mode>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 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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>Fuel Delivery and Evaporation Lines . Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>Fuel Injector .

No: Go to 2
CHECK DTC .
Read the engine DTC using the Subaru Select Monitor or general scan tool. Ref. 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)". Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>List of Diagnostic Trouble Code (DTC) .

No: Go to 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) (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
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". Ref. 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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>Fuel Pressure Sensor .
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". Ref. 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. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Diagnostics for Engine Starting Failure>FUEL PUMP CIRCUIT .
CHECK FUEL PRESSURE (LOW PRESSURE SIDE) .
Check the fuel pressure on low-pressure side. Ref. 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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>Fuel Pump>INSPECTION . Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>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 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". Ref. 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
CHECK HIGH-PRESSURE FUEL PUMP .
Check the high-pressure fuel pump. Ref. 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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>High Pressure Fuel Pump .
CHECK FOR REPRODUCTION OF FAILURE .
1. Perform the Clear Memory Mode. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Clear Memory Mode .
2. Perform appropriate drive cycle test. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Drive Cycle .
3. Read the DTC. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Read Diagnostic Trouble Code (DTC) .
Is DTC P0087 displayed?

Yes: Replace the high-pressure fuel pump. Ref. 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.
CHECK FOR REPRODUCTION OF FAILURE .
1. Perform the Clear Memory Mode. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Clear Memory Mode .
2. Perform appropriate drive cycle test. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Drive Cycle .
3. Read the DTC. Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Read Diagnostic Trouble Code (DTC) .
Is DTC P0087 displayed?

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 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". Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Subaru Select Monitor .
Does the value of «Fuel Rail Pressure A» decrease rapidly?

Yes: Replace the fuel injector. Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>Fuel Injector .

No: Repair the poor contact of ECM connector.