Code No. P1275: Supply Pump Exchange


FUNCTION



  • The engine-ECU monitors the signals input from the rail pressure sensor.
  • Based on these input signals, the engine-ECU checks whether the fuel pressure in the common rail is abnormal.

TROUBLE JUDGMENT


Check Conditions
  • Engine is running
  • Rail pressure sensor is normal
Judgment Criterion
  • The rail pressure continues to exceed the maximum operating pressure of the supply pump for 15 seconds.

FAIL-SAFE AND BACKUP FUNCTION



  • The rail pressure is controlled in the range between 50 and 60 MPa.
  • The fuel injection amount is restricted (Output restriction).
  • The open angle of the accelerator pedal is restricted.
  • The throttle valve is closed (except the driving conditions that the fuel pressure exceeds the seizure resistance) (Fixed opening degree).
  • The EGR control is stopped (fully closed).
  • The DPF regeneration is prohibited.
  • The AS&G control is prohibited.

PROBABLE CAUSES



  • Failed supply pump
  • Failed rail pressure sensor
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is any other diagnosis code than P1275 output?
Inspection chart for diagnosis codes (Refer to ).
Go to Step 2 .

STEP 2. Check suction control valve itself.

  • Check suction control valve itself (Refer to ).

Q. Is the check result normal?
Go to Step 3 .
Replace the suction control valve. After replacing the suction control valve, learn the supply pump. (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns <4N1> ).

STEP 3. Replace the supply pump.

  • After the supply pump assembly, learn the supply pump (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns <4N1> ).
  • After learning the supply pump, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Go to Step 4 .
The check is end.

STEP 4. Replace the common rail assembly and fuel injection tubes.

  • After replacing the common rail assembly and fuel injection tubes, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU.
The check is end.