Code No. U011B: Valve Lift ECU Time-out



caution Replace ECU after certainly confirming that the communication circuits are normal.

OPERATION




TROUBLE JUDGEMENT


Check Conditions
Judgement Criterion
  1. The system remains received no signals.
  2. The received target control angles remains out of a predetermined range.

COMMENTS ON TROUBLE SYMPTOM


Current malfunction
Past malfunction

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Perform voltage measurement at valve lift ECU connector.



  • Disconnect connector, and measure at harness side.
  • Voltage between terminal BAT1 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 2

    Repair or replace the connector, or check and repair harness between engine control relay connector terminal and valve lift ECU connector terminal BAT1, go to Step 10.

    • Check power supply line for open/short circuit.

STEP 2. Check harness between engine control relay connector terminal and valve lift ECU connector terminal BAT1.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 3.
Repair or replace the connector, or repair the damaged harness wire, go to Step 10.

STEP 3. Perform resistance measurement at valve lift ECU connector.



  • Disconnect connector, and measure at harness side.
  • Resistance between terminal GND and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 4.

    Repair or replace the connector, or check and repair the harness between the valve lift ECU connector terminal GND and body earth, go to Step 10.

    • Check earthing line for open circuit and damage.

STEP 4. Inspection of terminal resistors in the engine-ECU VCL-CAN.


caution A digital multimeter should be used. (Refer to GROUP 54C - Service Precautions ).

  • Disconnect engine-ECU connector, and then measure at the equipment side.
  • Resistance between terminal LCAH and LCAL.
OK: 100 - 140 Ω (at 20°C)

Q. Is the check result normal?

Go to Step 5.
Replace the engine-ECU, go to Step 10.

STEP 5. Inspection of terminal resistors in the valve lift ECU VCL-CAN.


caution A digital multimeter should be used. (Refer to GROUP 54C - Service Precautions ).

  • Disconnect valve lift ECU connector, and then measure at the equipment side.
  • Resistance between terminal LCAH and LCAL.
OK: 100 - 140 Ω (at 20°C)

Q. Is the check result normal?

Go to Step 6.
Replace the valve lift ECU, go to Step 10.

STEP 6. Check harness between engine-ECU connector terminal LCAH and valve lift ECU connector terminal LCAH.



  • Check signal line for open/short circuit and damage.

Q. Is the check result normal?

Go to Step 7.
Repair or replace the connector, or repair the damaged harness wire, go to Step 10.

STEP 7. Check harness between engine-ECU connector terminal LCAL and valve lift ECU connector terminal LCAL.



  • Check signal line for open/short circuit and damage.

Q. Is the check result normal?

Go to Step 8.
Repair or replace the connector, or repair the damaged harness wire, go to Step 10.

STEP 8. M.U.T.-III diagnosis code



  • Reconfirmation of diagnosis code.
Confirm again whether the diagnosis code is stored in the engine-ECU.

  1. Erase the stored diagnosis code.
  2. Ignition switch: LOCK (OFF) → ON
  3. Confirm whether the diagnosis code is stored.

Q. Is diagnosis code stored?

After replacing valve lift ECU, go to Step 9
Intermittent malfunction in CAN bus line between engine-ECU and valve lift ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 9. M.U.T.-III diagnosis code



  • Reconfirmation of diagnosis code.
Confirm again whether the diagnosis code is stored in the engine-ECU.

  1. Erase the stored diagnosis code.
  2. Ignition switch: LOCK (OFF) → ON
  3. Confirm whether the diagnosis code is stored.

Q. Is diagnosis code stored?

After replacing engine-ECU, go to Step 10
Intermittent malfunction in CAN bus line between engine-ECU and valve lift ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

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



  • Reconfirmation of diagnosis code.
Confirm again whether the diagnosis code is stored in the engine-ECU.

  1. Erase the stored diagnosis code.
  2. Ignition switch: LOCK (OFF) → ON
  3. Confirm whether the diagnosis code is stored.

Q. Is diagnosis code stored?

Go to Step 1.
Check end.