ECD SYSTEM(w/ DPF), Diagnostic DTC:P1271, P1272

DTC Code DTC Name
P1271 Fuel Regulator Circuit (EDU Drive)
P1272 Fuel Pressure Regulator Circuit

DESCRIPTION

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 ignition switch is turned off to allow prompt discharge of the common rail internal pressure and so that the engine stops smoothly.

Tech Tips


  • For more information on the pressure discharge valve and common rail system, refer to System Description Click here.

  • If P1271 and/or P1272 is present, refer to the DTC chart for the fuel system Click here.

B0027WFE07
B0024GTE01
Cross Section Diagram of Pressure Discharge Valve
*1 Return to Fuel Tank (Low Pressure)
*2 From Common Rail Assembly (High Pressure)
*3 Solenoid
*4 Valve
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P1271 Fuel Regulator Circuit (EDU Drive)

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)

Comes on DTC stored
P1272 Fuel Pressure Regulator Circuit

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

Comes on DTC stored
Related Data List
DTC No. Data List
P1271
  • Common Rail Pressure

  • Target Common Rail Pressure

  • Pressure Discharge Valve

P1272

Tech Tips


  • 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

CONFIRMATION DRIVING PATTERN

DTC No. DTC Detection Drive Pattern
P1271 Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal
P1272 Drive the vehicle at 50 km/h (31 mph) in third gear, and then decelerate by releasing the accelerator pedal. Perform this 5 times.

MONITOR DESCRIPTION



WIRING DIAGRAM

B0024XCE07
*a PLV
*b Pressure Discharge Valve

CAUTION / NOTICE / HINT

Note

After replacing the ECM, the new ECM needs registration (Click here ) and initialization Click here.

Tech Tips


  • After completing repairs, confirm that P1271 and/or P1272 do 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.

PROCEDURE


  1. CHECK IF DTC OUTPUT RECURS


    1. Connect the GTS to the DLC3.

    2. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs
    3. Turn the ignition switch off for 30 seconds or more.

    4. Turn the ignition switch to ON.

    5. 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.

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

    7. Read the pending DTCs.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Result Proceed to
      P1272 is output A
      P1271 is output B
      P1271 and P1272 are output
      Other DTCs are output C

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


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

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

      Click here


      Powertrain > Engine and ECT > Utility
      Tester Display
      Pressure Discharge Valve Check
    4. Select "Close to Open Check".

    5. Read the value of "Open and Engine OFF".

      OK
      0.5 MPa or less

      Tech Tips


      • When the system is normal, the value of "Open and Engine OFF" should be at or close to 0 MPa.

      • 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.

      • 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.

      • 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.

      Result
      Proceed to
      OK
      NG

    OK
    NG
  3. REPLACE COMMON RAIL ASSEMBLY


    1. Replace the common rail assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT
  4. BLEED AIR FROM FUEL SYSTEM


    1. Bleed the air from the fuel system.

      Click here

      Result
      Proceed to
      NEXT

    NEXT
  5. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

    2. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs
    3. Turn the ignition switch off for 30 seconds or more.

    4. Turn the ignition switch to ON.

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

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


      Powertrain > Engine and ECT > Trouble Codes
    7. Confirm that the DTC is not output again.

      Tech Tips

      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.


        Powertrain > Engine and ECT > Utility
        Tester Display
        All Readiness
      2. Input DTC P1271 and/or P1272.

      3. Check the DTC judgment result.

        Tech Tips

        Check that STATUS is NORMAL. 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
      Result Proceed to
      P1272 is output A
      No DTC is output B

    B
    A
  6. REPLACE FUEL SUPPLY PUMP ASSEMBLY


    1. Replace the fuel supply pump assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT
  7. BLEED AIR FROM FUEL SYSTEM


    1. Bleed the air from the fuel system.

      Click here

      Result
      Proceed to
      NEXT

    NEXT
  8. CHECK DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

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

    4. Read the DTCs.


      Powertrain > Engine > Trouble Codes
      Result
      Proceed to
      NEXT

    NEXT
  9. INSPECT COMMON RAIL ASSEMBLY (PRESSURE DISCHARGE VALVE RESISTANCE)


    1. Inspect the common rail assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG
    OK
  10. CHECK HARNESS AND CONNECTOR (PRESSURE DISCHARGE VALVE - ECM)


    1. Disconnect the pressure discharge valve connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Z3-2 (COM3) - C58-2 (PRV+) Always Below 1 Ω
      Z3-1 (PLV) - C58-1 (PRV-) Always Below 1 Ω
      Z3-2 (COM3) or C58-2 (PRV+) - Body ground and other terminals Always 10 kΩ or higher
      Z3-1 (PLV) or C58-1 (PRV-) - Body ground and other terminals Always 10 kΩ or higher
    4. Reconnect the pressure discharge valve connector.

    5. Reconnect the ECM connector.

      Result
      Proceed to
      OK
      NG

    NG
    OK
  11. CHECK IF DTC OUTPUT RECURS (DTC P1271 AND/OR P1272)


    1. Connect the GTS to the DLC3.

    2. Clear the DTCs.


      Powertrain > Engine and ECT > Clear DTCs
    3. Turn the ignition switch off for 30 seconds or more.

    4. Turn the ignition switch to ON.

    5. 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.

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

    7. Read the pending DTCs.


      Powertrain > Engine and ECT > Trouble Codes

      Tech Tips


      • If no pending DTCs are output, proceed to the next step to check "All Readiness".

      • 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.


        Powertrain > Engine and ECT > Utility
        Tester Display
        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

        Tech Tips

        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.


    A
    B
  12. REPLACE ECM


    1. Replace the ECM.

      Click here

      Result
      Proceed to
      NEXT

    NEXT
  13. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.

      Result
      Proceed to
      NEXT

    NEXT