Inspection Procedure 23: Fuel Pump System

OPERATION

The battery voltage is applied to the fuel pump relay (1) (terminal No. 3) form the ignition switch and is earthed to the vehicle body from the fuel pump relay (1) (terminal No. 2).
The battery voltage is applied to the fuel pump relay (1) (terminal No. 4) and to the fuel pump relay (2) (terminal No. 1) from the fuel pump relay (1) (terminal No. 1).
The battery voltage is applied to the fuel pump relay (2) (terminal No. 3) from the ignition switch. The engine-A/T-ECU (terminal No. 16) makes the power transistor in the unit be in ON position and makes currents go on the fuel pump relay (2) coil, and that makes the relay be in ON position.
When the fuel pump relay (2) is in ON position, the battery voltage is supplied to the fuel pump (low pressure) from the fuel pump relay (2) (terminal No. 4).

FUNCTION

When the ignition switch ON signal is input to the engine-A/T-ECU, the engine-A/T-ECU places the fuel pump relay in the ON position. Accordingly, the battery voltage is supplied to the fuel pump.

PROBABLE CAUSE

Failed fuel pump relay
Failed fuel pump
Open/short circuit in fuel pump drive circuit or loose connector contact
Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-216 fuel pump relay (1) connector and C-214 fuel pump relay (2) connector

Q. Is the check result normal?

Go to Step 2 .

Repair or replace.

STEP 2. Check fuel pump relay.

Fuel pump relay, continuity check (Refer to ).

Q. Is the check result normal?

	Go to Step 3 .

	Replace fuel pump relay.

STEP 3. Perform resistance measurement at C-216 fuel pump relay (1) connector.

Remove relay, and measure at junction block side.
Resistance between terminal No. 2 and earth.

OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 4 .

Check earthing line for open circuit and damage.

STEP 4. Perform voltage measurement at C-216 fuel pump relay (1) connector.

Remove relay, and measure at junction block side.
Ignition switch: ON
Voltage between terminal No. 3 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 6 .

Go to Step 5 .

STEP 5. Connector check: C-307 ignition switch connector

Q. Is the check result normal?

Check power supply line for open circuit and damage.

Repair or replace.

STEP 6. Perform voltage measurement at C-216 fuel pump relay (1) connector.

Remove relay, and measure at junction block side.
Voltage between terminal No. 4 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 7 .

Check power supply line for open/short circuit.

STEP 7. Perform voltage measurement at C-214 fuel pump relay (2) connector.

Remove relay, and measure at junction block side.
Ignition switch: ON
Voltage between terminal No. 3 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 9 .

Go to Step 8 .

STEP 8. Connector check: C-307 ignition switch connector

Q. Is the check result normal?

Check power supply line for open circuit.

Repair or replace.

STEP 9. Connector check: C-110 engine-A/T-ECU connector

Q. Is the check result normal?

Go to Step 10 .

Repair or replace.

STEP 10. Perform voltage measurement at C-110 engine-A/T-ECU connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 16 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 11 .

Check earthing line for open/short circuit.

STEP 11. Connector check: D-15 fuel pump connector

Q. Is the check result normal?

Go to Step 12 .

Repair or replace.

STEP 12. Perform voltage measurement at D-15 fuel pump connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Using a jumper wire, connect C-110 (terminal No. 16) engine-A/T-ECU connector and earth.
Voltage between terminal No. 5 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 15 .

Go to Step 13 .

STEP 13. Check harness between C-216 (terminal No. 1) fuel pump relay (1) connector and C-214 (terminal No. 1) fuel pump relay (2) connector.

Check power supply line for open/short circuit.

Q. Is the check result normal?

Go to Step 14

Repair.

STEP 14. Check harness between C-214 (terminal No. 4) fuel pump relay (2) connector and D-15 (terminal No. 5) fuel pump connector.

note

Before checking harness, check intermediate connectors D-210 and D-28, and repair if necessary.

Check power supply line for open/short circuit and damage.

Q. Is the check result normal?

Replace engine-A/T-ECU.

Repair.

STEP 15. Perform resistance measurement at D-15 fuel pump connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 4 and earth.

OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 16 .

Check earthing line for open circuit and damage.

STEP 16. Connector check: C-307 ignition switch connector

Q. Is the check result normal?

Go to Step 17 .

Repair or replace.

STEP 17. Check harness between C-307 (terminal No. 2) ignition switch connector and C-216 (terminal No. 3) fuel pump relay (1) connector.

note

Before checking harness, check intermediate connector C-202, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 18 .

Repair.

STEP 18. Check harness between battery and C-216 (terminal No. 4) fuel pump relay (1) connector.

note

Before checking harness, check intermediate connectors C-203, C-125, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 19 .

Repair.

STEP 19. Check harness between C-216 (terminal No. 1) fuel pump relay (1) connector and C-214 (terminal No. 1) fuel pump relay (2) connector.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 20 .

Repair.

STEP 20. Check harness between C-307 (terminal No. 2) ignition switch connector and C-214 (terminal No. 3) fuel pump relay (2) connector.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 21 .

Repair.

STEP 21. Check harness between C-214 (terminal No. 4) fuel pump relay (2) connector and D-15 (terminal No. 5) fuel pump connector.

note

Before checking harness, check intermediate connectors D-28 and C-210, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 22 .

Repair.

STEP 22. Check harness between C-214 (terminal No. 2) fuel pump relay (2) connector and C-110 (terminal No. 16) engine-A/T-ECU connector.

note

Before checking harness, check intermediate connectors C-18 and C-205, and repair if necessary.

Check earthing line for damage.

Q. Is the check result normal?

Replace fuel pump.

Repair.