Code No. P0628: Suction Control Valve Open

OPERATION

System power is supplied from the engine-ECU terminal (No. 17) to the suction control valve terminal (No. 1).
The engine ECU terminal (No. 37) turns on the power transistor to flow current to the suction control valve terminal (No. 2).

FUNCTION

The engine-ECU performs duty control over the suction control valve.
The engine-ECU checks whether the amount of current for driving duty is adequate.

TROUBLE JUDGMENT

Check Conditions

Battery positive voltage is 8 - 16 V
2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
The supply pump and injector are being normally controlled.
The fuel injection rate is 4 mm³/st or more.

Judgment Criterion

When the driving duty ratio of the suction control valve is higher than the specified value, the driving current is lower than the specified value.

FAIL-SAFE AND BACKUP FUNCTION

Rail pressure is controlled in the range from 50 to 100 MPa.
Fuel injection is restricted (output restriction).
The open angle of the accelerator pedal is controlled.
The throttle valve is shut (opening fixed).
Exhaust gas recirculation control is stopped (fully closed).

PROBABLE CAUSES

Failed suction control valve
Open circuit or harness damage in suction control valve circuit or loose connector contact

Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-29 suction control valve connector

Q. Is the check result normal?

	Go to Step 2 .

	Repair or replace the connector.

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. Perform voltage measurement at A-29 suction control valve connector.

Disconnect connector, and measurement at harness side.
Ignition switch: ON
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 7 .

	Go to Step 4 .

STEP 4. Connector check: C-116 engine-ECU connector.

Q. Is the check result normal?

	Go to Step 5 .

	Repair or replace the connector.

STEP 5. Check harness between C-116 (terminal No. 17) engine-ECU connector and A-29 (terminal No. 1) suction control valve connector.

Check power supply line for open circuit.

Q. Is the check result normal?

	Go to Step 6 .

	Repair the damaged harness wire.

STEP 6. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-ECU. 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 ).

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 7. Connector check: C-116 engine-ECU connector

Q. Is the check result normal?

	Go to Step 8 .

	Repair or replace the connector.

STEP 8. Check harness between C-116 (terminal No. 2) engine-ECU connector and A-29 (terminal No. 37) suction control valve connector.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 9 .

	Repair the damaged harness wire.

STEP 9. Check harness between C-116 (terminal No. 17) engine-ECU connector and A-29 (terminal No. 1) suction control valve connector.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 10 .

	Repair the damaged harness wire.

STEP 10. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-ECU. 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 ).

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).