Code No. P1274: Supply Pump Protection


OPERATION



  • Refer to Code No. P0191: Rail Pressure Sensor Range/Performance Problem .
  • Refer to Code No. P0192: Rail Pressure Sensor Circuit Low Input .
  • Refer to Code No. P0193: Rail Pressure Sensor Circuit High Input .

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
  • For 1 second, the rail pressure stays in the critical pressure range in which the supply pump in burned out.

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 P1274 set?
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 ).

STEP 3. Replace the supply pump assembly.

  • After the supply pump assembly, learn the supply pump (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).
  • After learning the supply pump assembly, 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. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
The check is end.