Dtc P1271 Fuel Regulator Circuit Malfunction (Edu Drive). Corolla Auris

DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

INSPECTION PROCEDURE

READ OUTPUT DTC

INSPECT PRESSURE DISCHARGE VALVE

CHECK WIRE HARNESS (EDU - PRESSURE DISCHARGE VALVE)

CHECK HARNESS AND CONNECTOR (EDU - ECM)

CHECK EDU (POWER SOURCE CIRCUIT)

REPLACE EDU

CHECK WHETHER DTC OUTPUT RECURS

REPLACE COMMON RAIL ASSEMBLY

DESCRIPTION

УКАЗАНИЕ:

1. For more information on the pressure discharge valve and the common rail system, refer to the following procedures (See page Нажмите здесь).
   
2. For more information on the EDU, refer to the following procedures (See page Нажмите здесь).
   
3. If P1271 and/or P1272 is present, refer to the DTC chart for the fuel system (See page Нажмите здесь).
   

УКАЗАНИЕ:

1. After confirming DTC P1271 and/or P1272, check the fuel pressure inside the common rail in the "Powertrain / Engine and ECT / Data List / Fuel Press" menu using the intelligent tester.
   
2. P1271:
   After clearing the DTC, drive the vehicle at 50 km/h (31 mph) with the third gear and then decelerate by releasing the accelerator pedal. Check that P1271 is not present.
   
3. P1272:
   After clearing the DTC, start and stop the engine twice, and then confirm that P1272 is not present.
   

MONITOR DESCRIPTION

1. P1271 (Open or short in pressure discharge valve circuit):
   This DTC will be set if there is no valve opening confirmation (IJf) signal sent from the EDU to the ECM, if the ECM has commanded the EDU to open the pressure discharge valve. This DTC refers to an open or short in the pressure discharge valve circuit, not a malfunction that includes a valve that is stuck open or closed.
   The EDU 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 EDU interprets this as the IJf signal is low. If this DTC is present, the ECM enters the fail-safe mode and limits engine power. The fail-safe mode continues until the ignition switch is turned off.
   
   
   
   
   

1. P1272 (Closed malfunction of the pressure discharge valve):
   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 judges that the valve is stuck closed and sets 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 present, the ECM enters a fail-safe mode and limits engine power. The fail-safe mode continues until the ignition switch is turned off.
   

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

INSPECTION PROCEDURE

ПРИМЕЧАНИЕ:

After replacing the ECM, the new ECM needs registration (see page Нажмите здесь) and initialization (see page Нажмите здесь).

УКАЗАНИЕ:

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 EDU and ECM, or there is an open in the wire harness for both injector and pressure discharge valve.
   

1. Connect the intelligent tester to the DLC3.
   

2. Turn the ignition switch on (IG) and turn the tester on.
   

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

4. Read DTCs.
   

   Result:

   Display (DTC Output)	Proceed to
   Only P1271, P1271 and P1272	A
   P1272 only	B

1. Disconnect the B87 pressure discharge valve connector.
   

2. Measure the resistance of the terminals of the pressure discharge valve.
   

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   B87-1 - B87-2	20°C (68°F)	0.85 to 1.05 Ω

3. Reconnect the pressure discharge valve connector.
   

1. Disconnect the B85 EDU connector.
   

2. Disconnect the B87 pressure discharge valve connector.
   

3. Measure the resistance of the wire harness side connectors.
   

   Standard resistance:

   Tester Connection	Specified Condition
   B85-3 (RLF+) - B87-2	Below 1 Ω
   B85-6 (RLF-) - B87-1	Below 1 Ω
   B85-3 (RLF+) or B87-2 - Body ground	10 kΩ or higher
   B85-6 (RLF-) or B87-1 - Body ground	10 kΩ or higher

4. Reconnect the EDU connector.
   

5. Reconnect the pressure discharge valve connector.
   

1. Disconnect the B84 EDU connector.
   

2. Disconnect the B31 ECM connector.
   

3. Measure the resistance of the wire harness side connectors.
   

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   B84-7 (PRD) - B31-52 (PRD)	Always	Below 1 Ω
   B84-7 (PRD) or B31-52 (PRD) - Body ground	Always	10 kΩ or higher

4. Reconnect the EDU connector.
   

5. Reconnect the ECM connector.
   

1. Disconnect the EDU connectors.
   

2. Turn the ignition switch on (IG).
   

3. Measure the voltage of the specified terminals of each EDU wire harness side connector.
   

   Standard voltage:

   Tester Connection	Condition	Specified Condition
   B86-3 (+B) - B86-2 (GND)	Ignition switch on (IG)	9 to 14 V

4. Reconnect the EDU connectors.
   

1. Replace the EDU (See page Нажмите здесь).
   

1. Connect the intelligent tester to the DLC3.
   

2. Turn the ignition switch on (IG) and turn the tester on.
   

3. Clear DTCs (See page Нажмите здесь).
   

4. Start the engine and drive the vehicle for approximately 15 minutes.
   

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

6. Read the DTCs.
   

   Result:

   Display (DTC Output)	Proceed to
   P1271 and/or P1272	A
   No output	B

1. Replace the common rail assembly (See page Нажмите здесь).