Engine Control Module Power Source Circuit: Highlander

For engine control module power source circuit inspection, see Fig 1-Fig 4 . 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 EFI main relay, see EFI MAIN RELAY  under MODULES, MOTORS, RELAYS & SOLENOIDS.

Fig 1: Engine Control Module Power Source Circuit Description & Diagram (Highlander)

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Fig 2: Engine Control Module Power Source Circuit Inspection - Steps 1-4 (Highlander)

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Fig 3: Engine Control Module Power Source Circuit Inspection - Steps 5-9 (Highlander)

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Fig 4: Identifying Engine Control Module Electrical Connector Terminals (Highlander)

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