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. 20 <Vehicle without immobilizer system>, 21 <Vehicle with immobilizer system>) 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
)
Q: Is the check result normal?
YES:
Go to Step 2 
.NO: Repair.
)
- 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?
YES:
Go to Step 4 .NO:
- Check intermediate connector C-205, and repair if necessary. If intermediate connector is normal, check and repair harness between C-215 (terminal No. 4) fuel pump relay (1) connector and body earth.
- Check earthing line for open circuit and damage.
- 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?
YES:
Go to Step 6 .NO: Go to Step 5
.)
Q: Is the check result normal?
YES:
- Check intermediate connector C-203, and repair if necessary. If intermediate connector is normal, check and repair harness between C-215 (terminal No. 3) fuel pump relay (1) connector and C-303 (terminal No. 2) ignition switch connector.
- Check power supply line for open circuit and damage.
- Remove relay and measure at junction block side.
- Voltage between terminal No. 1 and earth.
OK: System voltage
Q: Is the check result normal?
YES:
Go to Step 7 .NO:
- Check intermediate connectors C-116 and C-202, and repair if necessary. If intermediate connectors are normal, check and repair harness between C-215 (terminal No. 4) fuel pump relay (1) connector and battery.
- Check power supply line for open/short circuit.
)
- Remove relay, and measure at junction block side.
- Ignition switch: ON
- Resistance between terminal No. 2 and earth.
OK: 2 Ω
or less
Q: Is the check result normal?
YES:
Go to Step 9 .NO: Go to Step 8
.)
Q: Is the check result normal?
YES:
- Check intermediate connectors C-106 and C-205, and repair if necessary. If intermediate connectors are normal, check and repair harness between C-213 (terminal No. 2) fuel pump relay (2) connector and C-112 (terminal No. 20 engine-A/T-ECU connector.
- Check earthing line for open/short circuit.
- 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?
YES:
Go to Step 11 .NO: Go to Step 10
.
Q: Is the check result normal?
YES:
- Check intermediate connector C-203, and repair if necessary. If intermediate connector is normal, check and repair harness between C-213 (terminal No. 3) fuel pump relay (2) connector and C-303 (terminal No. 2) ignition switch connector.
- Check power supply line for open/short circuit.
- Remove relay, and measure at junction block side.
- Ignition switch: ON
- Voltage between terminal No. 1 and earth.
OK: System voltage
Q: Is the check result normal?
YES:
Go to Step 12 .NO:
- Check and repair harness between C-215 (terminal No. 1) fuel pump relay (1) connector and C-213 (terminal No. 1) fuel pump relay (2) connector.
- Check power supply line for open or short circuit.
)
Q: Is the check result normal?
YES:
Go to Step 13 .NO: Repair.
- 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?
YES:
Go to Step 16 .NO: Go to Step 14
.
NOTE: Before checking harness, check intermediate connector D-24, and repair if necessary.
- Check earthing line for open circuit and damage.
Q: Is the check result normal?
YES:
Go to Step 15 .NO: Repair.
- Disconnect connector, and measure at harness side.
- Ignition switch: ON
- Voltage between terminal No. 5 and earth.
OK: System voltage
Q: Is the check result normal?
YES:
Go to Step 21 .NO: Go to Step 17
.
NOTE: Check intermediate connectors D-24, C-117 and C-205, and repair if necessary.
- Check output line for open/short circuit.
Q: Is the check result normal?
YES:
Go to Step 18 .NO: Repair.
Q: Is the check result normal?
YES:
Go to Step 19 .NO: Repair.
NOTE: Before checking harness, check intermediate connector C-203, and repair if necessary.
- Check power supply line for damage.
Q: Is the check result normal?
YES:
Go to Step 20 .NO: Repair.
Q: Is the check result normal?
YES:
- Check intermediate connectors C-106 and C-205, and repair if necessary. If intermediate connectors are normal, check and repair harness between C-213 (terminal No. 2) fuel pump relay (2) connector and C-112 (terminal No. 20) engine-A/T-ECU connector.
- Check earthing line for damage.
Q: Is the check result normal?
YES:
Go to Step 22 .NO: Repair.
NOTE: Before checking harness, check intermediate connector C-203, and repair if necessary.
- Check power supply line for damage.
Q: Is the check result normal?
YES:
Go to Step 23 .NO: Repair.
NOTE: Before checking harness, check intermediate connectors C-116 and C-202, and repair if
necessary.
- Check power supply line for damage.
Q: Is the check result normal?
YES:
Go to Step 24 .NO: Repair.
- Check power supply line for damage.
Q: Is the check result normal?
YES:
Go to Step 25 .NO: Repair.
NOTE: Before checking harness, check intermediate connectors C-106 and C-205, and repair if
necessary.
- Check output line for damage.
Q: Is the check result normal?
YES:
Go to Step 26 .NO: Repair.
NOTE: Before checking harness, check intermediate connector D-24, and repair if necessary.
- Check earthing line for damage.
Q: Is the check result normal?
YES:
Replace fuel pump relay.NO: Repair.