P0088
DTC P0088 Fuel Rail / System Pressure - Too HighDESCRIPTION
DTC Detection Condition:
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
The high-pressure fuel system consists of the spill valve, pump plunger, check valve, relief valve and fuel pressure sensor. The spill 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 high-pressure side fuel pump is installed to the cylinder head cover (bank 1) and is driven by the cam located at the rear end of the exhaust camshaft.
Let the plunger moves up and down by the camshaft rotations, it produces 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 valve to regulate the fuel pressure to the target fuel pressure 4 to 13 MPa (40.8 to 132.6 kgf/sq.cm, 580 to 1,885 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 15 MPa (153 kgf/sq.cm, 2,175 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.
Wiring Diagram:
Step 1:
Step 1(Continued)-4:
INSPECTION PROCEDURE
HINT: Read freeze frame data using the intelligent tester. 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.