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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
  1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step  3.
  2. Connect hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. See Figure. Turn ignition on and then turn hand-held tester on. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate fuel pump. Listen for operating sound at in-tank fuel pump and feel for fuel pressure in the fuel return hose when slightly pinching the fuel return hose closed. Go to step  4.
  3. Remove glove box and heater duct (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure. Turn ignition on. Connect jumper wire between body ground and terminal No. 6 (Yellow wire) at ECM electrical connector E3 to operate the fuel pump. See Figure. This is the FC terminal on ECM. Listen for operating sound at in-tank fuel pump and feel for fuel pressure in the fuel return hose when slightly pinching the fuel return hose closed. Go to next step.
  4. If fuel pump does not operate, go to next step. If fuel pump operates, check starter signal circuit. See STARTER SIGNAL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If starter signal circuit is okay, go to next step. If starter signal circuit is defective, repair as necessary.
  5. Check Engine Control Module (ECM) power source circuit. See ENGINE CONTROL MODULE POWER SOURCE CIRCUIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If ECM power source circuit is okay, go to next step. If ECM power source circuit is defective, repair as necessary.
  6. Check operation of circuit opening relay. See CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If circuit opening relay operates properly, go to next step. If circuit opening relay is defective, replace circuit opening relay.
  7. Remove glove box and heater duct (if necessary) for access to ECM with electrical connectors still installed on ECM if not previously done. See Figure. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 6 (Yellow wire) at ECM electrical connector E3. See Figure. This is the FC terminal on ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check for open and short in wiring harness and electrical connectors between circuit opening relay and ECM. See WIRING DIAGRAMS article. It may be necessary to check IGN fuse, as it supplies voltage to one side of circuit opening relay. Circuit opening relay is located in fuse/relay box at driver's side front corner of engine compartment. Circuit opening relay may be marked as C/OPN relay in the fuse/relay box. IGN fuse is located in fuse box behind driver's side of instrument panel. Repair wiring harness or electrical connectors as necessary.
  8. Check fuel pump resistance and operation. See FUEL DELIVERY under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. 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. See FUEL PUMP under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
  9. Check operation of fuel pump relay. See FUEL PUMP RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If fuel pump relay operates properly, go to next step. If fuel pump relay is defective, replace relay.
  10. Check for open and short in wiring harness and electrical connectors between EFI main relay and circuit opening relay, and between circuit opening relay and fuel pump relay. See WIRING DIAGRAMS article. EFI main relay may also be referred to as EFI relay. EFI main relay and circuit opening relay are located in fuse/relay box at driver's side front corner of engine compartment. Circuit opening relay may be marked as C/OPN relay in the fuse/relay box. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connectors are defective, repair as necessary.
  11. Remove glove box and heater duct (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure. Using voltmeter, check voltage between body ground and terminal No. 4 (Black/Blue wire) at ECM electrical connector E3 with ignition switch in ON and START positions. See Figure. This is the FPR terminal on ECM. Voltage should be 0-3 volts with ignition switch in ON position and 9-14 volts with ignition switch in START position. If voltage is not within specification, go to next step. If voltage is within specification, check for open and short 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, replace ECM. If wiring harness and electrical connectors are defective, repair as necessary.
  12. Check for open and short in wiring harness and electrical connectors between fuel pump relay and ECM. See WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
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