Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive)

Engine Hybrid System. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25
1Kd-Ftv Engine Control. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25

DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK IF DTC OUTPUT RECURS

CHECK COMMON RAIL ASSEMBLY (PRESSURE DISCHARGE VALVE OPERATION)

INSPECT COMMON RAIL ASSEMBLY (PRESSURE DISCHARGE VALVE RESISTANCE)

CHECK HARNESS AND CONNECTOR (PRESSURE DISCHARGE VALVE - INJECTOR DRIVER)

CHECK HARNESS AND CONNECTOR (ECM - INJECTOR DRIVER)

INSPECT INJECTOR DRIVER (POWER SOURCE CIRCUIT)

REPLACE INJECTOR DRIVER

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

GO TO INJECTOR CIRCUIT

REPLACE ECM

REPLACE COMMON RAIL ASSEMBLY

BLEED AIR FROM FUEL SYSTEM

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

DTC P1271 Fuel Regulator Circuit Malfunction (EDU Drive)

DTC P1272 Fuel Pressure Regulator Malfunction


DESCRIPTION

The ECM controls the internal fuel pressure of the common rail 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. Also, the pressure discharge valve opens when the ignition switch is turned off to allow prompt discharge of the common rail internal pressure and so that the engine stops smoothly.
HINT:
  1. For more information on the pressure discharge valve and common rail system, refer to System Description (HILUX_TGN26 RM000000XSN01WX.html).
  2. For more information on the injector driver, refer to System Description (HILUX_TGN26 RM000000XSN01WX.html).
  3. If P1271 and/or P1272 is present, refer to the DTC chart for the fuel system (HILUX_TGN26 RM000000XSN01WX.html).

Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.1Kd-Ftv Engine Control.Ecd System (For Dpf). Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive)


Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.1Kd-Ftv Engine Control.Ecd System (For Dpf). Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive)


P1271
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch ON to off
and
Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal
Either condition is met (1 trip detection logic):
  1. Open or short in pressure discharge valve circuit.
  2. There is no valve opening confirmation (IJf) signal from the injector driver to the ECM for a specific number of times consecutively despite the ECM sending valve opening command (PRD) signals after the engine is started.
  1. Open or short in pressure discharge valve circuit
  2. Pressure discharge valve
  3. Injector driver

P1272
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch ON to off
Pressure discharge valve does not open.
Actual pressure decreasing rate deviates from the simulated pressure decreasing rate after the ignition switch is turned off (2 trip detection logic).
  1. Open or short in pressure discharge valve circuit (P1271 is stored simultaneously)
  2. Pressure discharge valve
  3. Injector driver
  4. ECM

Related Data List
DTC No.
Data List
P1271
  1. Fuel Press
  2. Target Common Rail Pressure
  3. Pressure discharge valve
P1272

HINT:
  1. 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 / Fuel Press.
  2. 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.
  3. P1272:
    After clearing the DTC, start and stop the engine twice (wait 30 seconds or more after turning the ignition switch off before starting the engine the second time), and then confirm that P1272 is not stored.

Reference
Engine Speed
Fuel Pressure (kPa)
Idling
Fuel press is within 5000 kPa of Target Common Rail Pressure
2500 rpm (No engine load)

MONITOR DESCRIPTION

  1. P1271 (Open or short in pressure discharge valve circuit):
    This DTC will be stored if there is no valve opening confirmation (IJf) signal sent from the injector driver to the ECM despite the ECM commanding the injector driver to open the pressure discharge valve. This DTC refers to an open or short circuit malfunction of the pressure discharge valve circuit, not a malfunction in which a valve is stuck open or closed.
    The injector driver monitors the current supplied to the pressure discharge valve to verify that the current flows into the valve. If the current exceeds the specified level, the injector driver interprets this as the IJf signal being low. If this DTC is stored, the ECM enters fail-safe mode and limits engine power. The ECM continues operating in fail-safe mode until the ignition switch is turned off.

    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.1Kd-Ftv Engine Control.Ecd System (For Dpf). Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive)

  1. P1272 (Pressure discharge valve stuck closed):
    The pressure discharge valve will open and discharge the internal fuel pressure from the common rail to the fuel tank when the ignition switch is turned off. In this event, the ECM compares the actual drop rate of the internal fuel pressure and the target drop rate. If the ECM judges that the actual drop rate is smaller than the target, the ECM then determines that the valve is stuck closed and stores this DTC. This DTC will be stored if the internal fuel pressure does not drop to the target after the ignition switch has been turned off.
    If this DTC is stored, the ECM enters fail-safe mode and limits engine power. The ECM continues operating in fail-safe mode until the ignition switch is turned off.

MONITOR STRATEGY


P1271
Required sensors
Injector driver
Frequency of operation
Continuous
Duration
3 seconds
MIL operation
1 driving cycle

P1272
Required sensors
Fuel pressure sensor
Frequency of operation
Once per driving cycle
Duration
1 second
MIL operation
2 driving cycles

TYPICAL ENABLING CONDITIONS


P1271
Specification
The vehicle is driven at 50 km/h (31 mph) in 3rd gear, and then decelerated by complete release of the accelerator pedal 3 times.

P1272
Item
Specification
Minimum
Maximum
Fuel pressure
27000 kPa (275 kgf/cm2, 3915 psi)
-
Fuel temperature
0°C (32°F)
-
Battery voltage
11 V
-
The monitor will not run if the fuel pressure sensor, pressure discharge valve circuit or fuel temperature sensor is malfunctioning.

TYPICAL MALFUNCTION THRESHOLDS


P1271
Specification
There are no confirmation signals from the injector driver for a specific number of times consecutively, despite the ECM sending command signals regularly during deceleration.

P1272
Specification
The internal pressure stays beyond the specified level after the ignition switch is turned off.

WIRING DIAGRAM


Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.1Kd-Ftv Engine Control.Ecd System (For Dpf). Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive)


INSPECTION PROCEDURE

NOTICE:
After replacing the ECM, the new ECM needs registration (HILUX_TGN26 RM0000012XK07FX.html) and initialization (HILUX_TGN26 RM000000TIN04CX.html).
HINT:
  1. After completing repairs, confirm that P1271 and/or P1272 does not recur.
  2. If P0200 and P1271 are present simultaneously, there is an open in the INJF wire harness between the injector driver and ECM, or there is an open in the wire harness for both an injector assembly and the pressure discharge valve.
  3. Read freeze frame data using the intelligent tester. 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

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (HILUX_TGN26 RM000000PDK12RX.html).

  1. Turn the ignition switch off for 30 seconds or more.

  1. Turn the ignition switch to ON.

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

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Read the pending DTCs.

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


B
Go to step 3

C
GO TO DTC CHART (HILUX_TGN26 RM0000031HW04SX.html)
A


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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Enter the following menus: Powertrain /Engine / Utility / Pressure Discharge Valve Check (HILUX_TGN26 RM0000012X104YX.html).

  1. Select "Close to Open Check".

  1. 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.


OK
Go to step 14

NG
Go to step 12

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

  1. Inspect the common rail assembly (HILUX_TGN26 RM000002SY301RX.html).



NG
Go to step 12
OK


4.CHECK HARNESS AND CONNECTOR (PRESSURE DISCHARGE VALVE - INJECTOR DRIVER)

  1. Disconnect the injector driver connector.

  1. Disconnect the pressure discharge valve connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C99-2 - C43-4 (RLF+)
    		Always
    		Below 1 Ω
    C99-1 - C44-1 (RLF-)
    		Always
    		Below 1 Ω
    C99-2 or C43-4 (RLF+) - Body ground
    		Always
    		10 kΩ or higher
    C99-1 or C44-1 (RLF-) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the injector driver connector.

  1. Reconnect the pressure discharge valve connector.



NG
Go to step 9
OK


5.CHECK HARNESS AND CONNECTOR (ECM - INJECTOR DRIVER)

  1. Disconnect the injector driver connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C45-2 (PRD) - C22-32 (PRD)
    		Always
    		Below 1 Ω
    C45-5 (INJF) - C22-25 (INJF)
    		Always
    		Below 1 Ω
    C45-2 (PRD) or C22-32 (PRD) - Body ground
    		Always
    		10 kΩ or higher
    C45-5 (INJF) or C22-25 (INJF) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the injector driver connector.

  1. Reconnect the ECM connector.



NG
Go to step 9
OK


6.INSPECT INJECTOR DRIVER (POWER SOURCE CIRCUIT)


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.1Kd-Ftv Engine Control.Ecd System (For Dpf). Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive)

  1. Disconnect the injector driver connectors.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    C43-2 (+B) - C43-3 (GND)
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Injector Driver)

  1. Reconnect the injector driver connector.



NG
Go to step 10
OK


7.REPLACE INJECTOR DRIVER

  1. Replace the injector driver (HILUX_TGN26 RM000004QZ200FX.html).


NEXT


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

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (HILUX_TGN26 RM000000PDK12RX.html).

  1. Turn the ignition switch off for 30 seconds or more.

  1. Turn the ignition switch to ON.

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

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. 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 tester 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
      Tester 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 3 times: drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal.


B
Go to step 11
A

END

9.REPAIR OR REPLACE HARNESS OR CONNECTOR

  1. Repair or replace the harness or connector.



NEXT
Go to step 14

10.GO TO INJECTOR CIRCUIT

  1. Go to injector circuit (HILUX_TGN26 RM000002V5Q05IX.html).



NEXT
Go to step 14

11.REPLACE ECM

  1. Replace the ECM (HILUX_TGN26 RM0000013Z001IX.html).



NEXT
Go to step 14

12.REPLACE COMMON RAIL ASSEMBLY

  1. Replace the common rail assembly (HILUX_TGN26 RM000002SY502LX.html).


NEXT


13.BLEED AIR FROM FUEL SYSTEM

  1. Bleed the air from the fuel system (HILUX_TGN26 RM000002SY8025X_01_0002.html).


NEXT


14.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (HILUX_TGN26 RM000000PDK12RX.html).

  1. Turn the ignition switch off for 30 seconds or more.

  1. Turn the ignition switch to ON.

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

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Confirm that the pending DTC is not output again.

    HINT:
    Perform the following procedure using the tester 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.

      HINT:
      If STATUS is INCOMPLETE or N/A, perform the following procedure 3 times: drive the vehicle at 50 km/h (31 mph) in 3rd gear, and then decelerate by completely releasing the accelerator pedal.

NEXT

END