Code No. P264C: Valve Lift Sensor Circuit Low Input

OPERATION

A power voltage of 5 V is applied to the valve lift sensor connector terminal from the engine-ECU connector terminal VLS5.
The power voltage is earthed to the engine-ECU connector terminal VLSE from the valve lift sensor connector terminal.
The sensor signal is inputted to the engine-ECU connector terminal VLS from the valve lift sensor output terminal.

FUNCTION

The valve lift sensor converts valve lift amount to voltage signal, and then sends it to the engine-ECU.
The engine-ECU uses this signal to control the valve lift mount.

TROUBLE JUDGMENT

Check Condition

After 2 seconds since the ignition switch is turned ON or since the completion of engine start.
Battery positive voltage is more than 10 V and is less than 16.5 V.

Judgement Criterion

Valve lift sensor output voltage is less than 0.2 V.

FAIL-SAFE AND BACKUP FUNCTION

The valve lift is fixed to maximum. Otherwise, deenergises the motor.
V.V.T. phase angle is set to most retarded position.

PROBABLE CAUSES

Failed valve lift sensor
Open/short circuit or harness damage in valve lift sensor circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Item 170: Valve lift sensor
Engine: Idle operation after warm-up

OK: 0.2 - 4.8 V (depends on engine operation condition)

Q. Is the check result normal?

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

	Go to Step 2.

STEP 2. Perform voltage measurement at valve lift sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal engine-ECU VLS5 line and body earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Check harness between valve lift sensor connector terminal and engine-ECU connector terminal VLS5.

Check power supply line for open/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 data list

Item 170: Valve lift sensor
Engine: Idle operation after warm-up

OK: 0.2 - 4.8 V (depends on engine operation condition)

Q. Is the check result normal?

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

	Replace the engine-ECU.

STEP 5. Check harness between valve lift sensor connector terminal and engine-ECU connector terminal VLS5.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 6.

	Repair or replace the connector, or repair the damaged harness wire.

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

Check output 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.

STEP 7. M.U.T.-III data list

Item 170: Valve lift sensor
Engine: Idle operation after warm-up

OK: 0.2 - 4.8 V (depends on engine operation condition)

Q. Is the check result normal?

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

	Go to Step 8.

STEP 8. Replace the valve lift sensor

After replacing the valve lift sensor, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Check end.