Inspection Procedure 19: Fuel Pump System
OPERATION
- The fuel pump drive power is supplied from engine control relay connector terminal to fuel pump relay (ETACS-ECU connector terminal F/PB) in the ETACS-ECU.
- The battery voltage is applied by the ignition switch connector terminal to the fuel pump relay coil (ETACS-ECU connector terminal IG1) in the ETACS-ECU. The engine-ECU connector terminal FP/R turns on the relay by turning ON the power transistor in the unit so as to conduct power to the fuel pump relay coil (via the ETACS-ECU connector terminal FP/R).
- When the fuel pump relay is turned ON, the battery voltage will be supplied from the fuel pump relay (ETACS-ECU connector terminal F/P) to the fuel pump.
FUNCTION
- When the ignition switch ON signal is inputted into the engine-ECU, the engine-ECU turns ON the fuel pump relay. This causes the battery voltage to be supplied to the fuel pump.
PROBABLE CAUSES
- Failed fuel pump relay in the ETACS-ECU
- Failed fuel pump
- Open/short circuit or harness damage in fuel pump drive circuit or loose connector contact
- Failed engine-ECU
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STEP 1. Check fuel pump relay.
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- Perform continuity test in fuel pump relay (Refer to
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Q.
Is the check result normal?
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 Go to Step 2.
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 Replace the ETACS-ECU.
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STEP 2. Voltage measurement at engine-ECU connector (FP/R terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the engine-ECU connector (FP/R terminal) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 3.
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Repair FP/R line between ETACS-ECU connector and engine-ECU connector.
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STEP 3. Voltage measurement at ETACS-ECU connector (F/PB terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the ETACS-ECU connector (F/PB terminal) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 4.
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Repair F/PB line between engine control relay connector and ETACS-ECU connector.
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STEP 4. Check fuel pump operations.
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- Check fuel pump operations (Refer to ).
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Q.
Is the check result normal?
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Go to Step 5.
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Replace the fuel pump and gauge assembly.
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STEP 5. Resistance measurement at fuel pump and gauge assembly connector (body earth line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the fuel pump and gauge assembly connector (body earth line) and body earth.
OK: Continuity (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 6.
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Repair body earth line between fuel pump and gauge assembly connector and body earth.
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STEP 6. Voltage measurement at fuel pump and gauge assembly connector (F/P line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the fuel pump and gauge assembly connector (F/P line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 8.
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Go to Step 7.
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STEP 7. Check of open circuit and short to earth in F/P line between ETACS-ECU connector and fuel pump and gauge assembly connector.
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Q.
Is the check result normal?
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Repair FP/R line between ETACS-ECU connector and engine-ECU connector.
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Repair the connector(s) or wiring harness.
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STEP 8. Check of damage in F/PB line between engine control relay connector and ETACS-ECU connector.
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Q.
Is the check result normal?
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Go to Step 9.
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Repair the connector(s) or wiring harness.
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STEP 9. Check of damage in F/P line between ETACS-ECU connector and fuel pump and gauge assembly connector.
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Q.
Is the check result normal?
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Go to Step 10.
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Repair the connector(s) or wiring harness.
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STEP 10. Check the fuel pump driving.
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- Ignition switch: ON
- Check for pump operating noise near fuel tank
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OK: Operating sound of fuel pump can be heard
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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Replace the engine-ECU.
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