P0088

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

DTC P0088 - Fuel Rail / System Pressure - Too High

DESCRIPTION

The high-pressure fuel system consists of the spill control valve, pump plunger, check valve, relief valve and fuel pressure sensor. The spill control valve opens and closes the low-pressure fuel line (from the fuel tank), the pump plunger (operated by the camshaft) pressurizes fuel, the check valve mechanically opens and closes the high pressure fuel line (to the fuel delivery pipe), the relief valve prevents fuel pressure from becoming extremely high, and the fuel pressure sensor located on the fuel delivery pipe monitors fuel pressure.
The fuel pump for high pressure is installed to the cylinder head cover (bank 1) and is driven by the cam located at the rear end of the exhaust camshaft.
The plunger moves up and down by the camshaft rotations, and produces a vacuum to suck fuel and pressurizes the fuel. This fuel then pushes the check valve open and flows into the fuel delivery pipe. The ECM opens and closes the spill control valve to regulate the fuel pressure to the target fuel pressure of 4 to 13 MPa (40.8 to 132.6 kgf/cm2, 580 to 1885 psi). In order to obtain and maintain the target pressure, the ECM monitors the fuel pressure using the fuel pressure sensor and performs the feedback control.
If the internal fuel pressure of the fuel delivery pipe exceeds the standard pressure of 15 MPa (153 kgf/cm2, 2175 psi), the fuel relief valve installed on gateway of the fuel delivery pipe discharges the fuel pressure and then returns the fuel back to the fuel tank.









MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM





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 Freeze Frame Data.

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) Clear the DTCs DTC Check / Clear.
(d) Start the engine.
(e) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes / Current.
(f) Read the DTCs using Techstream.
Result:





HINT:
If any codes other than P0088 are output, perform troubleshooting for those DTCs first.

B -- Go to DTC Chart Diagnostic Trouble Code Descriptions
A -- Continue to next step.
2. CHECK FUEL PRESSURE SENSOR
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Start the engine.
(d) Turn the Techstream on.
(e) Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Target Fuel Pressure / Fuel Press.
(f) Check if the fuel pressure fluctuates when the target fuel pressure changes.
HINT:
The Control the Target Fuel Pressure operation lowers the target fuel pressure by 12.5% or increases the target fuel pressure by 25%.

OK:
Fuel pressure fluctuates.
NG -- REPLACE FUEL PRESSURE SENSOR
OK -- Continue to next step.
3. REPLACE FUEL PUMP (FOR HIGH PRESSURE)
NEXT -- Continue to next step.
4. CHECK IF DTC OUTPUT REOCCURS (SEE IF DTC P0088 IS OUTPUT AGAIN)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Clear DTCs DTC Check / Clear.
(d) Start the engine.
(e) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes / Current.
(f) Read the DTCs using the Techstream.
Result:






B -- END
A -- REPLACE ECM