Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Fuel Rail / System Pressure - Too Low (P008700)

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Engine & Hybrid System / 2gr-fks (engine Control) / Sfi System / Fuel Rail / System Pressure - Too Low (P008700)

DESCRIPTION

The high-pressure direct injection fuel system consists of a spill control valve, check valve, fuel relief valve, fuel pressure sensor, fuel pump assembly (for high pressure side) and fuel injector assemblies (for direct injection). The spill control valve adjusts the return volume of high-pressure fuel. The check valve mechanically opens and closes the paths to the fuel delivery pipes. The relief valve releases the fuel back to the fuel tank if there is a malfunction in the high-pressure fuel system. The fuel pump assembly (for high pressure side) is installed to the cylinder head cover (bank 1) and operated by a cam installed to the end of the exhaust camshaft.

Rotation of the camshaft moves the pump plunger inside the fuel pump assembly (for high pressure side) up and down, pressurizing the fuel. The pressurized fuel opens the check valve and is pumped into the fuel delivery pipe. The ECM controls the spill control valve to adjust the fuel pressure between 2 and 25 MPa (20 and 255 kgf/cm2) and monitors signals from the fuel pressure sensor (for high pressure side) to maintain the target fuel pressure.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory	Note
P008700	Fuel Rail / System Pressure - Too Low	Although the ECM is not requesting the fuel pump assembly (for high pressure side) to open the spill control valve, fuel pressure decreases 5 MPa (51.0 kgf/cm2, 725 psi) from target pressure for about 10 seconds (1 trip detection logic).	Leak of fuel Fuel pipe (fuel tank - fuel pump assembly [for high pressure side]) Fuel pipe (fuel pump assembly [for high pressure side] - fuel injector assembly [for direct injection]) Fuel injector assembly (for direct injection) Fuel pump assembly (for high pressure side) Fuel pump (for low pressure side) Fuel pressure sensor (for high pressure side) Fuel system ECM	Comes on	DTC stored	SAE Code: P0087

MONITOR DESCRIPTION

If the fuel pressure decreases despite an increase request signal being sent to the fuel pump assembly (for high pressure side) by the ECM, the ECM will illuminate the MIL and store this DTC.

MONITOR STRATEGY

Related DTCs	P0087: Fuel pressure too low
Required Sensors/Components (Main)	Fuel pressure sensor (for high pressure side)
Required Sensors/Components (Related)	-
Frequency of Operation	Continuous
Duration	About 10 seconds
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored	None
Time after engine start	0.2 seconds or more
Time after fuel cut finished	3 seconds or more
Target fuel pressure	Small change

TYPICAL MALFUNCTION THRESHOLDS

Both of the following conditions are met	-
Difference in fuel pressure between actual and target	Less than -5 MPa (-51.0 kgf/cm2, -725 psi)
Actual discharge rate of high pressure fuel pump	400 mm3/st or more

CONFIRMATION DRIVING PATTERN

HINT:

When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
Click here
Permanent misfire and fuel system DTCs can only be cleared when performing the universal trip driving pattern when no malfunction is detected.

Connect the Techstream to the DLC3.
Turn the engine switch on (IG).
Turn the Techstream on.
Record the Freeze Frame Data.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for at least 30 seconds.
Start the engine.
Turn Techstream on.
Based on the engine speed, engine load and other conditions displayed in the freeze frame data, reproduce the conditions present when the DTC was stored.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P008700.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.

CAUTION / NOTICE / HINT

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 help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.	CHECK FUEL LEAK

(a) Check around and beneath the vehicle for fuel leaks, fumes, etc.

OK:

No fuel leaks present.

REPAIR OR REPLACE FUEL LEAK POINT

2.	CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P008700)

(a) Connect the Techstream to the DLC3.

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

(d) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result	Proceed to
DTC P008700 is output	A
DTC P008700 and other DTCs are output	B

HINT:

If any DTCs other than P008700 are output, troubleshoot those DTCs first.

GO TO DTC CHART

3.	CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

(a) Has the vehicle run out of fuel in the past?

YES

DTC CAUSED BY RUNNING OUT OF FUEL

4.	READ FREEZE FRAME DATA (TARGET FUEL PRESSURE (LOW) / TARGET FUEL PRESSURE 2 AND LOW FUEL PRESSURE SENSOR)

(a) Connect the Techstream to the DLC3.

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

(c) Using the Techstream, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

Powertrain > Engine > DTC(P008700) > Freeze Frame Data

Tester Display
Target Fuel Pressure (Low) / Target Fuel Pressure 2
Low Fuel Pressure Sensor

HINT:

Check the freeze frame data sets recorded the moment the DTC was stored and after the DTC was stored.
Using the freeze frame data, confirm the vehicle conditions when the DTC was stored, such as if the engine was idling with the shift state P, D or N or if the vehicle was being driven at a constant speed or accelerating.

(d) Compare the difference in pressure between "Target Fuel Pressure (Low) / Target Fuel Pressure 2 and Low Fuel Pressure Sensor".

Result	Proceed to
Difference between Target Fuel Pressure (Low) / Target Fuel Pressure 2 and Low Fuel Pressure Sensor is within 200 kPa	A
Difference between Target Fuel Pressure (Low) / Target Fuel Pressure 2 and Low Fuel Pressure Sensor is more than 200 kPa	B

GO TO FUEL PUMP CONTROL CIRCUIT

5.	CHECK MISFIRE COUNT OF DIRECT INJECTION

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Mode / Direct / Data List / Injection Mode and Misfire Count Cylinder #1 to Misfire Count Cylinder #6.

Powertrain > Engine > Active Test

Active Test Display
Control the Injection Mode

Data List Display
Injection Mode
Misfire Count Cylinder #1
Misfire Count Cylinder #2
Misfire Count Cylinder #3
Misfire Count Cylinder #4
Misfire Count Cylinder #5
Misfire Count Cylinder #6

HINT:

When using the "Control the Injection Mode" Active Test to check the condition of the engine, switch from "Port" to "Direct".
Do not switch from "Direct" to "Port". When performing the inspection more than once, after the Active Test ends, lightly race the engine, and then perform the inspection from "Port" again.
If the display does not switch from "Port" even after lighting racing the engine, idle the engine for approximately 1 minute, and then lightly race the engine.

(e) Monitor all of the Misfire Count values that are displayed on the Techstream.

Injection Mode	Misfire Count	Proceed to
Direct	No misfire counts, or misfire counts occur randomly in all cylinders	A
Direct	Misfire counts occur in a particular cylinder	B

HINT:

Perform "Inspection After Repair" after replacing the fuel injector assembly (for direct injection).

Click here

REPLACE FUEL INJECTOR ASSEMBLY (FOR DIRECT INJECTION)

6.	CHECK FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE)

(a) Connect the Techstream to the DLC3.

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

Powertrain > Engine > Data List

Tester Display
Fuel Pressure (High)

(d) Start the engine.

(e) Check that the fuel pressure fluctuates when the engine condition changes from idling to racing.

Result	Proceed to
Fuel pressure does not rise	A
Fuel pressure does not fluctuate	B
Fuel pressure fluctuates	C

HINT:

Perform "Inspection After Repair" after replacing the fuel pressure sensor (for high pressure side).

Click here

REPLACE FUEL DELIVERY PIPE WITH SENSOR ASSEMBLY LH (FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE))

GO TO STEP 9

7.	CHECK FUEL PUMP OPERATION (FOR LOW PRESSURE SIDE)

(a) Check the fuel pump operation (for low pressure side).

Click here

GO TO FUEL PUMP CONTROL CIRCUIT

8.	CHECK FUEL PRESSURE (FOR LOW PRESSURE SIDE)

(a) Check the fuel pressure (for low pressure side).

Click here

REPAIR OR REPLACE FUEL SYSTEM

9.	REPLACE FUEL (ENGINE ROOM SIDE) PUMP ASSEMBLY (FOR HIGH PRESSURE SIDE)

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

Click here

HINT:

Perform "Inspection After Repair" after replacing the fuel pump assembly (for high pressure side).

Click here

10.	CHECK IF DTC OUTPUT RECURS (SEE IF DTC P008700 IS OUTPUT AGAIN)

(a) Connect the Techstream to the DLC3.

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

Powertrain > Engine > Clear DTCs

(d) Turn the engine switch off and wait for at least 30 seconds.

(e) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

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

(g) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTC P008700 is output	B

END

REPLACE ECM

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