Dtc P0088 Fuel Rail / System Pressure - Too High

DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0088)

CHECK FREEZE FRAME DATA (COMMON RAIL PRESSURE)

CHECK WIRE HARNESS (FUEL PRESSURE SENSOR AND ECM)

REPLACE FUEL SUPPLY PUMP ASSEMBLY (SUCTION CONTROL VALVE)

BLEED AIR FROM FUEL SYSTEM

PERFORM SUPPLY PUMP INITIALIZATION

CHECK DTC OUTPUT

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK WIRE HARNESS (FUEL PRESSURE SENSOR AND ECM)

REPLACE COMMON RAIL ASSEMBLY (FOR BANK 1) (FUEL PRESSURE SENSOR)

BLEED AIR FROM FUEL SYSTEM

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

DESCRIPTION

HINT:

1. For more information on the fuel supply pump assembly (suction control valve) and common rail system, refer to System Description (Click here).
   
2. When DTC P0088 is stored, check the internal fuel pressure of the common rail assembly by entering the following menus: Engine and ECT / Data List / Common Rail Pressure.
   
   

   Reference

   Engine Speed	Common Rail Pressure
   Idling	Approximately 27000 to 49000 kPa
   3000 rpm (No engine load)	Approximately 57000 to 77000 kPa

3. Check "Common Rail Pressure", "Target Common Rail Pressure" and "Target Pump SCV Current" in the freeze frame data.
   

MONITOR DESCRIPTION

1. P0088 (Internal fuel pressure too high):
   The ECM stores this DTC if the fuel pressure inside the common rail assembly is higher than 250000 kPa (2550 kgf/cm², 36250 psi). This DTC indicates that: 1) the suction control valve may be stuck open, or 2) there may be a short in the suction control valve circuit.
   If this DTC is stored, the ECM enters fail-safe mode and limits the engine power. The ECM continues operating in fail-safe mode until the engine switch is turned off.
   

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

1. After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).
   
2. After replacing the fuel supply pump assembly, the ECM needs initialization (Click here).
   
3. After replacing an injector assembly, the ECM needs registration (Click here).
   

HINT:

Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

1. Connect the GTS to the DLC3.
   

2. Turn the engine switch on (IG) and turn the GTS on.
   

3. Enter the following menus: Engine and ECT / Trouble Codes.
   

4. Read Current DTCs.
   
   

   Result

   Result	Proceed to
   P0088 is output	A
   P0088 and "P0190, P0192 or P0193" are output	B

   HINT:

   When there is an open circuit in the fuel pressure sensor circuit, the fuel pressure sensor outputs the maximum value. Therefore, P0088 may be stored together with DTCs which indicate common rail fuel pressure sensor circuit malfunctions.

1. Connect the GTS to the DLC3.
   

2. Turn the engine switch on (IG) and turn the GTS on.
   

3. Enter the following menus: Engine and ECT / Trouble Codes.
   

4. Record the stored DTCs and freeze frame data.
   
   

   Result

   Result	Proceed to
   Value of Common Rail Pressure is shifting towards 160000 kPa or higher in 3rd and 4th set of freeze frame data	B
   Except above	A

HINT:

If the MIL has illuminated before in the past, clear the DTC using the GTS before performing this inspection (Click here).

1. Check if the MIL lights up when vibration is applied to the wire harness and connectors between the fuel pressure sensor and ECM.
   
   

   Result:

   
   

   Result	Proceed to
   MIL does not come on	A
   MIL comes on	B

1. Replace the fuel supply pump assembly (Click here).
   

   HINT:

   Before replacing the fuel supply pump assembly, check that the wire harness between the suction control valve and ECM is not shorted to ground.

   When there is a malfunction in the wire harness, Target Pump SCV Current is outside the range of 802 to 1202 mA when idling, and outside the range of 840 to 1240 mA when the engine is running at 2500 rpm without load.

   If there are no problems with the engine condition during idling, it is not necessary to perform the above wire harness inspection.

   When the wire harness between the suction control valve and ECM is not shorted to ground, it can be assumed that DTC P0088 was stored due to a malfunction in the operation of the suction control valve. Therefore, it is necessary to replace the fuel supply pump assembly.

1. Bleed the air from the fuel system (Click here).
   

2. Perform PM forced regeneration (Click here).
   

   HINT:

   When fuel lines are disconnected, air may enter the fuel lines, leading to engine starting trouble. Therefore, perform forced regeneration and bleed the air from the fuel lines.

1. Perform supply pump initialization (Click here).
   

1. Connect the GTS to the DLC3.
   

2. Clear the DTCs (Click here).
   

3. Turn the engine switch off for 30 seconds or more.
   

4. Turn the engine switch on (IG) and start the engine.
   

5. After idling for 60 seconds, increase the engine speed from idling to 2500 rpm repeatedly for 30 seconds.
   

6. Confirm that the DTC is not output again.
   

   HINT:

   Perform the following procedure using the GTS to determine whether or not the DTC judgment has been carried out.

   1. Enter the following menus: Engine and ECT / Utility / All Readiness.
      

   2. Input DTC P0088.
      

   3. Check the DTC judgment result.
      
      

      Result

      GTS Display	Result	Proceed to
      Pending DTC	P0088 is output	A
      All Readiness	NORMAL	B
      	ABNORMAL	A

      HINT:

      If STATUS is INCOMPLETE or N/A, race the engine to 2500 rpm repeatedly for 30 seconds and increase the idling time.

1. Replace the ECM (Click here).
   

1. Repair or replace the harness or connector.
   

HINT:

If the MIL has illuminated before in the past, clear the DTC using the GTS before performing this inspection (Click here).

1. Check if the MIL lights up when vibration is applied to the wire harness and connectors between the fuel pressure sensor and ECM.
   
   

   Result:

   
   

   Result	Proceed to
   MIL does not come on	A
   MIL comes on	B

1. Replace the common rail assembly (for bank 1) (Click here).
   

1. Bleed the air from the fuel system (Click here).
   

2. Perform PM forced regeneration (Click here).
   

   HINT:

   When fuel lines are disconnected, air may enter the fuel lines, leading to engine starting trouble. Therefore, perform forced regeneration and bleed the air from the fuel lines.

1. Connect the GTS to the DLC3.
   

2. Clear the DTCs (Click here).
   

3. Turn the engine switch off for 30 seconds or more.
   

4. Turn the engine switch on (IG) and start the engine.
   

5. After idling for 60 seconds, increase the engine speed from idling to 2500 rpm repeatedly for 30 seconds.
   

6. Confirm that the DTC is not output again.
   

   HINT:

   Perform the following procedure using the GTS to determine whether or not the DTC judgment has been carried out.

   1. Enter the following menus: Engine and ECT / Utility / All Readiness.
      

   2. Input DTC P0088.
      

   3. Check that STATUS is NORMAL. If STATUS is INCOMPLETE or N/A, race the engine to 2500 rpm repeatedly for 30 seconds and increase the idling time.