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 seconds, the rail pressure stays in the critical pressure range in which the supply pump is burned out.

PROBABLE CAUSES



  • Failed supply pump
  • Failed common rail assembly
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

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

Q. Is any other diagnosis code than P1274 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 supply pump assembly. After replacing the supply pump, 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 - 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 ).
The check is end.