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

• 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.
  

• 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
  

Q. Is the check result normal? Go to Step 2 . Repair or replace the connector.

	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 ).

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 .

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.

Q. Is the check result normal? Go to Step 6 . Repair or replace the connector.

Q. Is the check result normal? Go to Step 7 . Repair the damaged harness wire.

	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 ).