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 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 ).

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 DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration

	The check is end.