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.

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

Q. Is the check result normal?

	Go to Step 2.

	Replace the water level switch.

STEP 2. Voltage measurement at water level switch connector (IG11 line).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Ignition switch: ON

(3)Check the voltage between the ETACS-ECU connector (IG11 terminal) and body earth.
OK: System voltage

Q. Is the check result normal?

	Go to Step 3.

	Repair IG11 line between ETACS-ECU connector and water level switch connector.

STEP 3. Check of damage in IG11 line between ETACS-ECU connector and water level switch connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

STEP 4. Check of open circuit, short to earth, and damage in WLS line between engine-ECU connector and water level switch connector.

Q. Is the check result normal?

	Go to Step 5.

	Repair the connector(s) or wiring harness.

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).