Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Checking Fuel Pump Operation Using Scan Tool (LX470)
2004 Toyota Celica GT, StandardSECTION Checking Fuel Pump Operation Using Scan Tool (LX470)
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Lexus SC 430, 2003 Lexus RX 300, 2003 Lexus LX 470, 2003 Lexus LS 430, and 2003 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
- Connect scan tool to Data Link Connector (DLC) No. 3, located under left side of instrument panel. Turn ignition on. DO NOT start engine. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump.
- Remove engine cover, above intake manifold. Engine cover must be removed for access to fuel pressure pulsation damper located at firewall end of driver's side fuel rail. See Fig 1.
- Listen for operating sound at fuel pump and check that screw at center of fuel pressure pulsation damper moves upward due to fuel pressure. See Fig 1. If fuel pump operates, check fuel pressure. See FUEL PRESSURE . If fuel pump does not operate, go to next step.
- Check for defective fuses/fusible links. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If fuses/fusible links are okay, check for defective fuel pump. See CHECKING FUEL PUMP OPERATION BY APPLYING BATTERY VOLTAGE TO FUEL PUMP . Replace fuel pump as necessary. If fuel pump operates, go to next step.
- EFI main relay, fuel pump Electronic Control Unit (ECU) or fuel pump switch may be defective, or fuel pump switch may need to be reset. If problem exists with fuel pump ECU or wiring circuit, a Diagnostic Trouble Code (DTC) P1200 should be stored in Engine Control Module (ECM). Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - LX470 article. For testing of EFI main relay or fuel pump switch, see SYSTEM & COMPONENT TESTING - LX470 article.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.