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 JUDGEMENT

Check Conditions

Engine is running
Rail pressure sensor is normal

Judgement 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.

Suction control valve connector check.
Check suction control valve itself (Refer to ).

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the connector, or 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.

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, erasing the diagnosis code through M.U.T.-III, ignition switch is "ON" position and confirm whether the diagnosis code is set.

Q. Is diagnosis code No. P1275 set again?

	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, erasing the diagnosis code through M.U.T.-III, ignition switch is "ON" position and confirm whether the diagnosis code is set.

Q. Is diagnosis code No. P1275 set again?

	Replace the engine-ECU.

	The check is end.