1Gd-Ftv Engine Control. Dtc P1271 Fuel Regulator Circuit (Edu Drive)

The ECM controls the internal fuel pressure of the common rail assembly by opening and closing the pressure discharge valve. When sudden deceleration occurs, the internal fuel pressure will temporarily become higher than usual and combustion noise may result. Therefore the ECM will open the valve temporarily to discharge the excess pressure inside the common rail assembly. Also, the pressure discharge valve opens when the engine switch is turned off to allow prompt discharge of the common rail internal pressure and so that the engine stops smoothly.

HINT:

For more information on the pressure discharge valve and common rail system, refer to System Description (LandCruiser RM000000XSN04NX.html).
If P1271 and/or P1272 is present, refer to the DTC chart for the fuel system (LandCruiser RM000000XSN04NX.html).

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System.
Dtc
P1271 Fuel Regulator Circuit (Edu Drive)

P1271
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal	When the condition below is met a certain number of times (0.5 seconds) (1 trip detection logic): Open or short in pressure discharge valve circuit.	Open or short in pressure discharge valve circuit Pressure discharge valve (common rail assembly)

P1272
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal. Perform this 5 times.	The fuel pressure does not decrease while the engine is running (1 trip detection logic)	Open or short in pressure discharge valve circuit (P1271 is stored simultaneously) Pressure discharge valve (common rail assembly) ECM

Related Data List
DTC No.	Data List
P1271 P1272	Common Rail Pressure Target Common Rail Pressure Pressure Discharge Valve

HINT:

After confirming DTC P1271 and/or P1272, check the fuel pressure inside the common rail by entering the following menus: Powertrain / Engine and ECT / Data List / Common Rail Pressure.
P1271:
After clearing the DTC, drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal. Check that P1271 is not output.
P1272:
After clearing the DTC, perform the following procedure 5 times, and then check that P1272 is not output: Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal.

Reference
Engine Speed	Common Rail Pressure (kPa)
Idling	Common Rail Pressure is within 5000 kPa of Target Common Rail Pressure
3000 rpm (No engine load)

Results of Real-vehicle Check
Condition	Common Rail Pressure (Idling)	Common Rail Pressure (1 Second after Engine Stopped)
Pressure discharge valve normal	35000 kPa	500 kPa
Open in pressure discharge valve circuit	35000 kPa	30000 kPa

MONITOR DESCRIPTION

P1271 (Open or short in pressure discharge valve circuit):
This DTC is output when there is an open or short circuit in the pressure discharge valve circuit. When this DTC is output, the ECM enters fail-safe mode and restricts the engine output. The ECM stays in fail-safe mode until the engine switch is turned off.

P1272 (Pressure discharge valve stuck closed):
The pressure discharge valve opens when the common rail target fuel pressure decreases during deceleration, decreasing the fuel pressure in the common rail assembly. The ECM compares the speed that the fuel pressure decreases with the speed that the common rail target fuel pressure decreases.
When the ECM determines that the decreasing rate of the fuel pressure is smaller than the common rail target fuel pressure, the ECM determines that the valve is stuck closed or there is an injection or supply pump assembly malfunction (overpressure) and outputs this DTC.
When this DTC is output, the ECM enters fail-safe mode and restricts the engine output. The ECM stays in fail-safe mode until the engine switch is turned off.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

After replacing the ECM, the new ECM needs registration (LandCruiser RM0000012XK0AUX.html) and initialization (LandCruiser RM000000TIN08HX.html).

HINT:

After completing repairs, confirm that P1271 and/or P1272 does not recur.
Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

1.CHECK IF DTC OUTPUT RECURS

Connect the GTS to the DLC3.

Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

Turn the engine switch off for 30 seconds or more.

Turn the engine switch on (IG) and turn the GTS on.

Drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal. Perform this 5 times.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the pending DTCs.

Result
Result
Proceed to
DTC P1272 is output
A
DTC P1271 is output
B
DTC P1271 and P1272 are output
Other DTCs are output
C

Result
Result	Proceed to
DTC P1272 is output	A
DTC P1271 is output	B
DTC P1271 and P1272 are output
Other DTCs are output	C

Go to step 5

GO TO DTC CHART (LandCruiser RM0000031HW07OX.html)

A

2.CHECK COMMON RAIL ASSEMBLY (PRESSURE DISCHARGE VALVE OPERATION)

Connect the GTS to the DLC3.

Turn the engine switch on (IG) and turn the GTS on.

Enter the following menus: Powertrain /Engine and ECT / Utility / Pressure Discharge Valve Check.

Select "Close to Open Check".

Read the value of "Open and Engine OFF".
OK:
0.5 MPa or less
HINT:
1. When the system is normal, the value of "Open and Engine OFF" should be at or close to 0 MPa.
2. When the fuel pressure value of "Open and Engine OFF" does not become equal to or less than 0.5 MPa, the pressure discharge valve may be stuck closed.
3. When the fuel pressure values of "Close and Engine OFF" and "Open and Engine OFF" are both 0 MPa, the pressure discharge valve may be stuck open or there may be a fuel leak.
4. Perform "Always Closed Check" if the value is not 0 MPa when the pressure discharge valve is open during "Close to Open Check". If the results are the same as during "Close to Open Check", there is a pressure discharge valve operation malfunction.

Go to step 10

OK

3.CHECK DTC OUTPUT (DTC P1272)

Connect the GTS to the DLC3.

Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

Turn the engine switch off for 30 seconds or more.

Turn the engine switch on (IG) and turn the GTS on.

Drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal. Perform this 5 times.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTC.

Result
Result
Proceed to
DTC P1272 is output
A
DTC is not output
B

Result
Result	Proceed to
DTC P1272 is output	A
DTC is not output	B

END

A

4.REPLACE FUEL SUPPLY PUMP ASSEMBLY

Replace the fuel supply pump assembly (LandCruiser RM000005UHX000X.html).

Go to step 11

5.INSPECT COMMON RAIL ASSEMBLY (PRESSURE DISCHARGE VALVE RESISTANCE)

Inspect the common rail assembly (LandCruiser RM000005UHY000X_01_0001.html).

Go to step 10

OK

6.CHECK HARNESS AND CONNECTOR (PRESSURE DISCHARGE VALVE - ECM)

Disconnect the pressure discharge valve connector.

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
r9-2 - C150-2 (PRV+)	Always	Below 1 Ω
r9-1 - C150-1 (PRV-)	Always	Below 1 Ω
r9-2 or C150-2 (PRV+) - Body ground and other terminals	Always	10 kΩ or higher
r9-1 or C150-1 (PRV-) - Body ground and other terminals	Always	10 kΩ or higher

Reconnect the pressure discharge valve connector.

Reconnect the ECM connector.

Go to step 9

OK

7.CHECK IF DTC OUTPUT RECURS (DTC P1271 AND/OR P1272)

Connect the GTS to the DLC3.

Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

Turn the engine switch off for 30 seconds or more.

Turn the engine switch on (IG) and turn the GTS on.

Drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal. Perform this 5 times.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the pending DTCs.
HINT:
1. If no pending DTCs are output, proceed to the next step to check "All Readiness".
2. Perform the following procedure using the GTS to determine whether or not the DTC judgment has been carried out.
1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
2. Input DTC P1271 and P1272.
3. Check the DTC judgment result.
  
  Result
  GTS Display
  Result
  Proceed to
  Pending DTC
  P1271 and/or P1272 is output
  B
  All Readiness
  NORMAL
  A
  ABNORMAL
  B
  HINT:
  If STATUS is INCOMPLETE or N/A, perform the following procedure 5 times: drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal.

Result
GTS Display	Result	Proceed to
Pending DTC	P1271 and/or P1272 is output	B
All Readiness	NORMAL	A
ABNORMAL	B

END

B

8.REPLACE ECM

Replace the ECM (LandCruiser RM0000013Z002DX.html).

Go to step 12

9.REPAIR OR REPLACE HARNESS OR CONNECTOR

Repair or replace the harness or connector.

Go to step 12

10.REPLACE COMMON RAIL ASSEMBLY

Replace the common rail assembly (LandCruiser RM000005UI0000X.html).

NEXT

11.BLEED AIR FROM FUEL SYSTEM

Bleed the air from the fuel system (LandCruiser RM000002SY803FX_01_0002.html).

NEXT

12.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the GTS to the DLC3.

Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

Turn the engine switch off for 30 seconds or more.

Turn the engine switch on (IG) and turn the GTS on.

Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal. Perform this 5 times.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Confirm that the DTC is not output again.
HINT:
Perform the following procedure using the GTS to determine whether or not the DTC judgment has been carried out.
1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
2. Input DTC P1271 and/or P1272.
3. Check the DTC judgment result.
  HINT:
  If STATUS is INCOMPLETE or N/A, perform the following procedure 5 times: drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal.

END