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Fuel Pump Control Circuit: Sequoia

NOTE: On Sequoia, if problem exists in fuel pump control circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM).
  1. If using Toyota hand-held tester, go to next step. If Toyota hand-held tester is not available, go to step  3.
  2. Check operation of fuel pump by using Toyota hand-held tester. See FUEL PUMP OPERATION under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. Ensure screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure. Fuel pressure pulsation damper is located at firewall end of driver's side fuel rail. See Fig 1. If screw at center of fuel pressure pulsation damper does not rise upward when fuel pump is operated to indicate fuel pressure, go to step  4. If screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure, go to step  11.
    Fig 1: Locating Fuel Pressure Pulsation Damper & Screw (Sequoia)
    G99G08301Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Remove glove box and heater duct for access to Engine Control Module (ECM). For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. See Figure. Turn ignition on. Momentarily connect jumper wire between body ground and terminal No. 6 (Green/Orange wire) at ECM electrical connector E4 to operate fuel pump. This is the FC terminal at ECM. Ensure screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure. Fuel pressure pulsation damper is located at firewall end of driver's side fuel rail. See Fig 1. If screw at center of fuel pressure pulsation damper does not rise upward when fuel pump is operated to indicate fuel pressure, go to next step. If screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure, go to step  11.
  4. Check ECM power source circuit. See ENGINE CONTROL MODULE POWER SOURCE CIRCUIT . If ECM power source circuit is okay, go to next step. If ECM power source circuit is defective, repair as necessary.
  5. Check operation of fuel pump relay. See FUEL PUMP RELAY  under MODULES, MOTORS, RELAYS & SOLENOIDS. If fuel pump relay operates properly, go to next step. If fuel pump relay is defective, replace fuel pump relay.
  6. Check operation of circuit opening relay. See CIRCUIT OPENING RELAY  under MODULES, MOTORS, RELAYS & SOLENOIDS. If circuit opening relay operates properly, go to next step. If circuit opening relay is defective, replace circuit opening relay.
  7. Check fuel pump resistance and operation. See FUEL DELIVERY  under FUEL SYSTEMS. If fuel pump resistance is within specification and fuel pump operates, go to next step. If fuel pump resistance is not within specification or fuel pump does not operate, replace fuel pump.
  8. Check for open in wiring harness and electrical connectors between fuel pump relay and fuel pump, and between fuel pump and body ground. See WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
  9. Remove glove box and heater duct for access to ECM if not previously done. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. See Figure.
  10. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 6 (Green/Orange wire) at ECM electrical connector E4. This is the FC terminal at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See TROUBLE SHOOTING - NO CODES article. If voltage is not within specification, check for open in wiring harness and connectors between FC terminal at ECM and circuit opening relay, and between ignition switch and EFI main relay. See WIRING DIAGRAMS article. It may be necessary to check EFI No. 1 fuse. EFI No. 1 fuse is located in fuse/relay box at driver's side front corner of engine compartment, near battery. Repair wiring harness or electrical connectors as necessary.
  11. Check fuel pump resistor. See FUEL DELIVERY  under FUEL SYSTEMS. If fuel pump resistor is okay, go to next step. If fuel pump resistor is defective, replace fuel pump resistor.
  12. Check for open in wiring harness and electrical connectors between fuel pump relay and fuel pump resistor, and between fuel pump resistor and fuel pump. If wiring harness and electrical connectors are okay, test is complete.
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