Code No. P0004: Suction Control Valve Battery Short


OPERATION



  • The voltage is applied from the engine-ECU connector terminal SCV+ to the suction control valve connector terminal via the power transistor in the engine-ECU.
  • The voltage is earthed to the engine-ECU connector terminal SCV- from the suction control valve connector terminal.

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 amount 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.

FAIL-SAFE AND BACKUP FUNCTION



  • The rail pressure is controlled in the range between 50 and 100 MPa.
  • The fuel injection amount is restricted (Output restriction).
  • The open angle of the accelerator pedal is restricted.
  • The throttle valve is closed (Fixed opening degree).
  • The EGR control is stopped (fully closed).
  • The DPF regeneration is prohibited.
  • The AS&G control is prohibited.

PROBABLE CAUSES



  • Failed suction control valve
  • Short circuit in suction control valve circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSTIC PROCEDURE

STEP 1. 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 2.
Repair or replace the connector, or replace the suction control valve.

STEP 2. Check harness between engine-ECU connector terminal SCV+ and suction control valve connector terminal.

  • Check power supply line for short circuit.

Q. Is the check result normal?
Go to Step 3.
Repair or replace the connector, or repair the damaged harness wire.

STEP 3. Check harness between engine-ECU connector terminal SCV- and suction control valve connector terminal.

  • Check earthing line for short circuit.

Q. Is the check result normal?
Go to Step 4.
Repair or replace the connector, or repair the damaged harness wire.

STEP 4. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

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