2001 Honda Prelude Base, StandardFACTORY OEM SERVICE PROCEDURE

Reverse Lock System

NOTE: For circuit identification and component locations, see WIRING DIAGRAMS  .
  1. Turn ignition on. Check if "D4" indicator light on instrument panel is flashing. If "D4" indicator light is flashing, diagnose A/T electronic control system. See M6HA DIAGNOSIS article. If "D4" indicator light is not flashing, go to next step.
  2. Place shift lever in "P" position. Measure voltage between passenger's multiplex control unit harness connector terminals No. 14 (Black wire) and No. 16 (Black/Blue wire). See Figure . If voltage does not exist, go to next step. If voltage exists, repair open in Black/Blue wire between multiplex control unit harness connector and A/T gear position switch. See WIRING DIAGRAMS  .
  3. Turn ignition off. Disconnect passenger's multiplex control unit harness connector. Turn ignition on. Place shift lever in "N" position. Check voltage between passenger's multiplex control unit harness connector terminals No. 14 (Black wire) and No. 15 (Green/Yellow wire). If voltage does not exist, go to next step. If voltage exists, repair open in circuit between passenger's multiplex control unit and shift lock relay, and A/T gear position switch.
  4. Turn ignition off. Disconnect shift lock solenoid harness connector. Check for continuity between passenger's multiplex control unit harness connector terminal No. 15 (Green/Yellow wire) and shift lock solenoid harness connector terminal No. 2 (Green/Yellow wire). If continuity exists, go to next step. If continuity does not exist, repair open in Green/Yellow wire between multiplex control unit and shift lock solenoid.
    5. CAUTION: DO NOT connect battery voltage to shift lock solenoid connector terminal No. 2 (Green/Yellow wire). Diode inside shift lock solenoid will be damaged.
  5. Connect battery voltage to shift lock solenoid connector terminal No. 1 (Yellow/Red wire), and connect ground to shift lock solenoid connector terminal No. 2 (Green/Yellow wire). Shift lock solenoid should click. If shift lock solenoid operates properly, go to next step. If solenoid does not operate properly, replace shift lock solenoid. See SHIFT LOCK SOLENOID  under REMOVAL & INSTALLATION.
  6. Check for loose passenger's multiplex control unit harness connectors. Repair as necessary. If connectors are okay, substitute a known-good passenger's multiplex control unit and retest.
Factory Service Tools

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When to See a Mechanic

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

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

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