Code No. P0629: Suction Control Valve Battry Short




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 lower than the specified value, the driving current is higher than the specified value.

PROBABLE CAUSES



  • Failed suction control valve
  • Open/short circuit in suction control valve circuit or loose connector contact

  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-47 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 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. Perform voltage measurement at A-47 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 5 .

Go to Step 4 .

STEP 4. Connector check: C-105 engine-ECU connector


Q. Is the check result normal?


    Check and repair harness between C-105 (terminal No. 17) engine-ECU connector and A-47 (terminal No. 1) suction control valve connector.

    • Check power supply line for short circuit.

Repair or replace the connector.

STEP 5. Connector check: C-105 engine-ECU connector.

Q. Is the check result normal?

Go to Step 6 .

Repair or replace the connector.

STEP 6. Check harness between C-105 (terminal No. 37) engine-ECU connector and A-47 (terminal No. 2) suction control valve connector.


Q. Is the check result normal?

Go to Step 7 .

Repair the damaged harness wire.

STEP 7. M.U.T.-III diagnosis code.

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
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 ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).