Tundra 3.4L

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2003 Toyota Tundra, 2003 Toyota Tacoma, 2003 Toyota Sienna, 2003 Toyota Sequoia, and 2003 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.

For engine control module power source circuit inspection, see Fig 1-Fig 5 . For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Fig 1: Engine Control Module Power Source Circuit Description & Diagram (Tundra 3.4L)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Engine Control Module Power Source Inspection - Steps 1-3 (Tundra 3.4L)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 3: Engine Control Module Power Source Inspection - Steps 4-6 (Tundra 3.4L)

Fig 4: Engine Control Module Power Source Inspection - Steps 7-9 (Tundra 3.4L)

Fig 5: Identifying Engine Control Module Electrical Connector Terminals (Tundra 3.4L)