1991 Acura Legend Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Code 15: Ignition Output Signal

NOTE: For wiring diagrams, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section. For vacuum diagrams, see VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section.
  1. Turn ignition off. Remove ACG fuse in underdash fuse box for 10 seconds to reset ECU. Start engine, and connect jumper wire to diagnostic connector. Observe CHECK ENGINE light. If light is not flashing, problem is intermittent. Check for poor and loose connections at ignitor, ECU and wires in connectors C380 and C382 under right side of dash. Test drive, and check again.
  2. If CHECK ENGINE light flashes Code 15, turn ignition off. Disconnect 8-pin connector on ignitor unit. Check continuity between Black wire terminals and ground.
  3. If continuity is present, go to next step. If no continuity is present, repair open in Black wire(s) between ignitor unit and ground.
  4. Disconnect 6-pin connector from ignitor. Connect ECU test harness between ECU and ECU connector. See Figure . Check for continuity between body ground terminals A21, A22, B3, B4, B6 and B8. If no continuity is present between any of these terminals and ground, go to next step. Repair short in wire if any wire has continuity to ground.
  5. Check each wire between ECU and 6-pin connector at ignitor. Repair any open wires. If all wires are okay, replace ignitor. Retest system for Code 15. If no code is flashed, replace ignitor.
  6. If Code 15 is still present, substitute a known good ECU, and recheck. If condition goes away, replace ECU.
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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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