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 D-4S (Direct Injection 4-stroke Gasoline Engine Superior Version) is a high-pressure fuel system. It consists of the following: 1) a spill control valve, which adjusts the discharge amount of the high-pressure fuel; 2) a pump plunger, which operates with the camshaft and pressurizes the fuel; and 3) a check valve, which mechanically opens and closes the pathway to the fuel delivery pipe.
The high-pressure fuel pump is installed on the cylinder head cover (bank 1). It operates with the rear tip of the exhaust camshaft. As the camshaft rotates, the pump plunger is moved up and down, the fuel is pressurized, the high-pressure fuel pushes open the check valve, and the high-pressure fuel flows to the fuel delivery pipe.
The ECM controls the spill control valve, adjusts the fuel pressure to 4 to 13 MPa (40.8 to 132.6 kgf/cm2), and maintains the target fuel pressure by monitoring the signals from the fuel pressure sensor. If the fuel pressure in the fuel delivery pipe increases to 15.3 MPa (156 kgf/cm2), the fuel relief valve is mechanically opened and fuel is returned to the fuel tank.
Immediately after the power switch is turned off, the ECM opens the fuel relief valve to lower the fuel pressure (high-pressure side). This is performed to help prevent fuel leaks as a result of residual pressure.
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
System monitor:
Closed stuck:
TYPICAL MALFUNCTION THRESHOLDS
System monitor:
Close stuck:
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 power switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(d) Read the DTCs using the Techstream.
Result:
HINT: If any codes other than P0088 are output, perform troubleshooting for those DTCs first.
B -- GO TO DTC CHART
A -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM (FP REL VLV)
(a) Put the engine in inspection mode Inspection Mode Procedure.
(b) Warm up the engine.
(c) Connect the Techstream to the DLC3.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press and Coolant Temp and Battery Voltage.
NOTICE:
- Coolant Temp value is 50°C (122°F) or more
- Battery Voltage value is 10 V or more
- Fuel Press value is 2 MPa or more
(f) Turn the power switch off.
(g) Wait for 10 seconds.
(h) Put the engine in inspection mode.
(i) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
(j) After starting the engine, turn the power switch off within 45 seconds.
HINT: Before turning the power switch off, write down the Fuel Press value.
(k) Wait for 10 seconds. Then turn the power switch on (IG).
(l) Enter the following menus: Powertrain / Engine and ECT / Active Test / Fuel Pressure Relief Valve open / Fuel Press and Coolant Temp and Battery Voltage.
(m) Before turning the power switch off, check if the Fuel Press value is stable.
HINT: Before performing the Active Test, check that the following conditions are met.
- Coolant Temp value is 50°C (122°F) or more
- Battery Voltage value is 10 V or more
- Fuel Press value is 2 MPa or more
(n) Set Fuel Pressure Relief Valve Open to ON and open the fuel relief valve.
NOTICE:
- Wait 30 seconds after turning the power switch on (IG). If ON Is selected before 30 seconds have passed, the Active Test will not operate.
- After selecting ON, the Active Test will turn off automatically after 2 seconds have passed.
- After ON is selected, ON will not be operable for 60 seconds.
(o) After performing the Active Test, check the fuel pressure.
Result:
B -- INSPECT FUSE (RELIEF VLV)
A -- 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) Clear DTCs DTC Check / Clear.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Connect the Techstream to the DLC3.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(f) Read the DTCs using the Techstream.
Result:
B -- END
A -- Continue to next step.
5. PERFORM ACTIVE TEST USING TECHSTREAM (TARGET FUEL PRESS)
(a) Put the engine in inspection mode Inspection Mode Procedure.
(b) Connect the Techstream to the DLC3.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Target Pressure / Fuel Press.
(e) Check that the fuel pressure fluctuates when the target fuel pressure changes.
HINT: The Control the Target Press operation lowers the target fuel pressure by 12.5% or increase the target fuel pressure 25%.
OK:
Fuel pressure fluctuates.
NG -- REPLACE FUEL PRESSURE SENSOR
OK -- REPLACE ECM
6. INSPECT FUSE (RELIEF VLV)
(a) Remove the RELIEF VLV fuse from the engine room No. 1 junction block.
(b) Check the RELIEF VLV fuse resistance.
Standard resistance:
Below 1 Ohms
(c) Reinstall the RELIEF VLV fuse.
NG -- CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE
OK -- Continue to next step.
7. INSPECT RELIEF VLV RELAY
(a) Remove the RELIEF VLV relay from the engine room No. 1 relay block.
(b) Measure the resistance of the fuel relief valve relay.
Standard resistance:
NG -- REPLACE FUEL RELIEF VALVE RELAY
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (RELIEF VLV RELAY - ECM, RELIEF VLV RELAY - FUEL RELIEF VALVE, FUEL RELIEF VALVE - BODY GROUND)
(a) Remove the RELIEF VLV relay from the engine room No. 1 relay block.
(b) Disconnect the A53 ECM connector.
(c) Disconnect the E82 fuel relief valve connector.
(d) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. REPLACE FUEL RELIEF VALVE
NEXT -- Continue to next step.
10. PERFORM ACTIVE TEST USING TECHSTREAM (FP REL VLV)
(a) Put the engine in inspection mode Inspection Mode Procedure.
(b) Warm up the engine.
(c) Connect the Techstream to the DLC3.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press and Coolant Temp and Battery Voltage.
NOTICE:
- Coolant Temp value is 50°C (122°F) or more
- Battery Voltage value is 10 V or more
- Fuel Press value is 2 MPa or more
(f) Turn the power switch off.
(g) Wait for 10 seconds.
(h) Put the engine in inspection mode.
(i) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
(j) After starting the engine, turn the power switch off within 45 seconds.
HINT: Before turning the power switch off, write down the Fuel Press value.
(k) Wait for 10 seconds. Then turn the power switch on (IG).
(l) Enter the following menus: Powertrain / Engine and ECT / Active Test / Fuel Pressure Relief Valve Open / Fuel Press and Coolant Temp and Battery Voltage.
(m) Before turning the power switch off, check if the Fuel Press value is stable.
HINT: Before performing the Active Test, check that the following conditions are met.
- Coolant Temp value is 50°C (122°F) or more
- Battery Voltage value is 10 V or more
- Fuel Press value is 2 MPa or more
(n) Set Fuel Pressure Relief Valve Open to ON and open the fuel relief valve.
NOTICE:
- Wait 30 seconds after turning the power switch on (IG). If ON is selected before 30 seconds have passed, the Active Test will not operate.
- After selecting ON, the Active Test will turn off automatically after 2 seconds have passed.
- After ON is selected, ON will not be operable for 60 seconds.
(o) After performing the Active Test, check the fuel pressure.
OK:
Fuel pressure decreases
NG -- REPLACE ECM
OK -- END