Code No. P2648: Valve Lift Control Motor Coil Open


OPERATION



  • Controls the current that is applied from the valve lift ECU connector terminal VLMV, VLMU and VLMW to the valve lift control motor connector terminal.

FUNCTION



  • The valve lift ECU rotates the worm shaft when the three-phase coil of the valve lift control motor is energised sequentially and variably.

TROUBLE JUDGMENT


Check Conditions
  • Engine starting sequence was completed.
  • The valve lift ECU has determined that the system communicates with the engine-ECU via VLC-CAN normally.
Judgement Criteria
  • The engine-ECU has received malfunction from the valve lift ECU via VLC-CAN.
  • Contents of malfunction which the valve lift ECU detects

  1. When the power supply voltage to the valve lift control motor is 8 V or more, all the terminal voltages at U, V and W phases are 7 V or less.

FAIL-SAFE AND BACKUP FUNCTION



  • Deenergises the valve lift control motor.

PROBABLE CAUSES



  • Open circuit or harness damage in valve lift control motor circuit or loose connector contact.
  • Failed valve lift control motor.
  • Failed valve lift ECU

DIAGNOSIS PROCEDURE

STEP 1. Check valve lift control motor itself.

  • Valve lift control motor connector check.
  • Check valve lift control motor (Refer to ).

Q. Is the check result normal?
Go to Step 2.
Repair or replace the connector, or replace the valve lift control motor.

STEP 2. Check harness between valve lift control motor connector terminal and valve lift ECU connector terminal VLMV.

  • Check power supply line for open circuit and damage.

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 valve lift control motor connector terminal and valve lift ECU connector terminal VLMU.

  • Check power supply line for open circuit and damage.

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

STEP 4. Check harness between valve lift control motor connector terminal and valve lift ECU connector terminal VLMW.

  • Check power supply line for open circuit and damage.

Q. Is the check result normal?
Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is diagnosis code set?

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