P0088

2GR-FSE ENGINE CONTROL: SFI SYSTEM: P0088: Fuel Rail / System Pressure - Too High
P0088 - Fuel Rail / System Pressure - Too High

DESCRIPTION

The direct injection high-pressure fuel system has a spill control valve, pump plunger and check valve. The spill control valve adjusts the discharge amount of the high-pressure fuel, the pump plunger operated by the camshaft pressurizes the fuel, the check valve mechanically opens and closes the line to the fuel delivery pipe. The fuel pump for high pressure is installed to the cylinder head cover (bank 1) and is driven by the cam lobe located at the rear end of the bank 1 exhaust camshaft. When the plunger moves up and down due to camshaft rotation, it pressurizes the fuel. The pressurized fuel then pushes open the check valve, and the fuel flows to the fuel delivery pipe. The ECM controls the spill control valve to adjust the fuel pressure to 4 to 13 MPa (41 to 133 kgf/cm2). The ECM receives signals from the fuel pressure sensor, monitors the fuel pressure, and maintains the target fuel pressure. If the fuel pressure of the fuel delivery pipe exceeds 15 MPa (153 kgf/cm2), the fuel relief valve opens and returns the fuel to the fuel tank.









MONITOR DESCRIPTION

If the fuel pressure does not decrease even after the ECM commands the high-pressure fuel pump to open the spill control valve, a DTC is output.

If there is minimal difference between the fuel pressure before and after the fuel relief valve operates, a DTC is output.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





CONFIRMATION DRIVING PATTERN

- Connect the Techstream to the DLC3.

- Turn the engine switch on (IG) and turn the Techstream on.

- Record the Freeze Frame Data.

- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) DTC Check / Clear.

- Turn the engine switch off and wait for 30 seconds.

- Turn the engine switch on (IG) and turn the Techstream on.

- Based on engine rpm, engine load and other freeze frame data stored in the ECM, reproduce the conditions present when the DTC was stored.

- Enter the following menus: Powertrain / Engine / Utility / All Readiness.

- Input the DTC: P0088.

- Check the DTC judgment result.





HINT
If the judgment result shows ABNORMAL, the system has a malfunction.

- If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Code / Pending.

- Read Pending DTCs.

HINT
If a pending DTC is output, the system is malfunctioning.

- If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
INSPECTION PROCEDURE

HINT
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0088)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and turn the Techstream ON.

(c) Enter the following menus: Powertrain / Engine / Trouble Codes.

(d) Read the DTCs.

Result:





HINT
If any DTCs other than P0088 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART SFI System
A -- Continue to next step.

2. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Start the engine and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Active Test / Control the Target Fuel Press / Fuel Press.

(d) Check that the fuel pressure fluctuates when the target fuel pressure changes.

HINT
The Active Test operation lowers the target fuel pressure by 12.5% or increase the target fuel pressure by 25%.

OK:

Fuel pressure fluctuates.

NG -- REPLACE FUEL PRESSURE SENSOR
OK -- Continue to next step.

3. REPLACE FUEL PUMP ASSEMBLY (FOR HIGH PRESSURE)

(a) Replace the fuel pump assembly (for high pressure) Removal.

NEXT -- Continue to next step.

4. CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0088 IS OUTPUT AGAIN)

(a) Connect the Techstream to the DLC3.

(b) Turn the Techstream on.

(c) Clear the DTCs DTC Check / Clear.

(d) Start the engine.

(e) Enter the following menus: Powertrain / Engine / Trouble Codes.

(f) Read the DTCs.

Result:





B -- END

A -- REPLACE ECM Removal