Inspection Procedure 21: Water Level Switch System

OPERATION

The battery voltage is applied to the water level switch connector terminal from the ETACS-ECU connector terminal IG11.
The ON/OFF signal is inputted to the engine-ECU connector terminal WLS from the water level switch output terminal.

FUNCTION

Detect the amount of water accumulated in the fuel filter and input the information to the engine-ECU. When the water level is higher than the specified value, the water level switch is turned ON. This allows the engine-ECU to send the request signal of the water level warning-display to the combination meter through CAN.

PROBABLE CAUSES

Failed water level switch
Open/short circuit or harness damage in water level switch circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check water level switch itself.

Water level switch connector check.
Check water level switch itself (Refer to GROUP 13B - Fuel Filter <4N1> - Fuel Filter Inspection ).

Q. Is the check result normal?

	Go to Step 2.

	Repair or replace the connector, or replace the water level switch.

STEP 2. Perform voltage measurement at water level switch connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal ETACS-ECU IG11 line and body earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the connector, or check and repair harness between water level switch connector terminal and ETACS-ECU connector terminal IG11. Check power supply line for open/short circuit.

STEP 3. Check harness between ETACS-ECU connector terminal IG11 and water level switch connector terminal.

Check power supply line for 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 water level switch connector terminal and engine-ECU connector terminal WLS.

Check output line for open/short 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. Check the trouble symptoms.

Q. Does the trouble symptom persist?

	Replace the engine-ECU.

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