Driver's Multiplex Control Unit

2004 Acura 3.5RLSECTION Driver's Multiplex Control Unit
  1. Remove driver's underdash fuse/relay box. See DRIVER'S UNDERDASH FUSE/RELAY BOXΒ  under REMOVAL & INSTALLATION. Remove driver's multiplex control unit from driver's underdash fuse/relay box. Disconnect control unit connectors. Inspect connectors and terminals. Check for bent, loose, or corroded terminals. Perform driver's multiplex control unit input tests. See Fig 1 . Repair as necessary and recheck system operation. If driver's multiplex control unit inputs are okay, go to next step.
  2. Reconnect driver's multiplex control unit to driver's underdash fuse/relay box. Perform input tests at back of fuse/relay box (backprobe). See Fig 2 . Repair as necessary. If all tests are okay, driver's multiplex control unit may be faulty. Substitute known-good driver's multiplex control unit and retest system. If problem still exists, go to PASSENGER'S MULTIPLEX CONTROL UNITΒ  .
Fig 1: Driver's Multiplex Control Unit Anti-Theft System Input Test (1 Of 2)
G99H50028Courtesy of AMERICAN HONDA MOTOR CO., INC.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.