For more information on the pressure discharge valve and the common rail system, refer to the following procedures (See page Нажмите здесь).
For more information on the EDU, refer to the following procedures (See page Нажмите здесь).
If P1271 and/or P1272 is present, refer to the DTC chart for the fuel system (See page Нажмите здесь).
DTC No.
DTC Detection Condition
Trouble Area
P1271
Open or short in pressure discharge valve circuit. There is no valve opening confirmation (IJf) signal from EDU to ECM despite the ECM sending valve opening command (PRD) signal after the engine is started. (1-trip detection logic)
Open or short in pressure discharge valve circuit
Open or short in pressure discharge valve itself
EDU
ECM
P1272
Pressure discharge valve closed malfunction. Actual pressure decreasing rate deviates from the simulated pressure decreasing rate after the ignition switch is turned off. (2-trip detection logic)
Open or short in pressure discharge valve circuit (P1271 is set simultaneously)
Pressure discharge valve
Supply pump
ECM
УКАЗАНИЕ:
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.
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.
P1272: After clearing the DTC, start and stop the engine twice, and then confirm that P1272 is not present.
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.
MONITOR STRATEGY
P1271:
Required sensors
EDU
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
Drive the vehicle at 50 km/h (31 mph) in 3rd gear and then decelerate by completely releasing the accelerator pedal
P1272:
Item
Specification
Minimum
Maximum
Fuel pressure
30 MPa (306 kgf/cm 2 , 4351 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 EDU, despite the ECM sending the command signals regularly during deceleration
P1272:
Specification
The internal pressure stays beyond the specified level after the ignition switch was turned off
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:
After completing repairs, confirm that P1271 and/or P1272 does not recur.
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.READ OUTPUT DTC
Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG) and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Result:
Display (DTC Output)
Proceed to
Only P1271, P1271 and P1272
A
P1272 only
B
B
Перейдите к шагу 8
A
2.INSPECT PRESSURE DISCHARGE VALVE
Disconnect the B87 pressure discharge valve connector.
Measure the resistance of the terminals of the pressure discharge valve.
