Inspection Procedure 21: Water Level Switch System


OPERATION



  • The battery voltage is applied to the water level switch (terminal No. 2) from the ETACS-ECU (terminal No. 5).
  • The ON/OFF signal is inputted to the engine-ECU (terminal No. 10) from the water level switch output terminal (terminal No. 1).

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. Connector check: A-06 water level switch connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. 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 3 .
Replace the water level switch.

STEP 3. Perform voltage measurement at A-06 water level switch connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 2 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 5 .

    Go to Step 4 .

STEP 4. Connector check: C-417 ETACS-ECU connector

Q. Is the check result normal?

    Check intermediate connector C-127, and repair if necessary. If intermediate connector is normal, check and repair harness between A-06 (terminal No. 2) water level switch connector and C-417 (terminal No. 5) ETACS-ECU connector.

    • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 5. Connector check: C-417 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 6 .
Repair or replace the connector.

STEP 6. Check harness between C-417 (terminal No. 5) ETACS-ECU connector and A-06 (terminal No. 2) water level switch connector.
note Before checking harness, check intermediate connector C-127, and repair if necessary.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

STEP 7. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?
Go to Step 8 .
Repair or replace the connector.

STEP 8. Check harness between A-06 (terminal No. 1) water level switch connector and B-09 (terminal No. 10) engine-ECU connector.

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

Q. Is the check result normal?
Go to Step 9 .
Repair the damaged harness wire.

STEP 9. 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 ).