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Power Circuits

  1. Using a voltmeter, check for battery voltage between ECU power terminal and ground. See POWER & GROUND CIRCUITS TERMINAL IDENTIFICATION  table. See Fig 1 . If battery voltage is not present, check appropriate ECU fuse in underhood fuse box. See ECU POWER CIRCUITS FUSE IDENTIFICATION  table. If fuse is okay, check for an open in wire between underhood fuse box and appropriate ECU power circuit terminal.
  2. Turn ignition switch to ON position. Using a voltmeter, check for battery voltage between appropriate ECU power circuit terminal and ground. See POWER & GROUND CIRCUITS TERMINAL IDENTIFICATION  table. See Fig 1 . If battery voltage is not present, check appropriate fuse in underhood fuse box. See ECU POWER CIRCUITS FUSE IDENTIFICATION  table. If fuse is okay, check for an open in wire between fuse box and appropriate ECU power circuit terminal or check for a defective ignition switch.
    POWER & GROUND CIRCUITS TERMINAL IDENTIFICATION

    Application (1) ECU Terminal
    Ground Circuits A2, A4, A16 & A18
    Power Circuits
    Ignition Switch In
    OFF Position B1
    ON Position A13 & A15
    (1) See Fig 1 for terminal location identification.
    ECU POWER CIRCUITS FUSE IDENTIFICATION

    Application (1) Fuse
    Ignition Switch In
    OFF Position HAZARD
    ON Position ECU
    (1) All fuses are in underhood fuse box.
    Fig 1: Identifying ECU Terminals
    G90F17140Courtesy of AMERICAN HONDA MOTOR CO., INC.
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