1987 Honda Prelude Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Code 8, CYL Sensor

  1. Turn ignition off. Remove No. 11 fuse in the under-hood relay box for 10 seconds to reset ECU. Start engine and observe PGM-FI warning light. If light is off, problem is intermittent. Test drive and check again.
  2. If light is on, turn ignition off. Disconnect sensor connector at distributor. Using an ohmmeter, measure resistance between Orange/Blue and White/Blue terminals. If reading is not 650 850 ohms, replace crank angle sensor. If reading is within specification, proceed to next step.
  3. Check continuity between ground and Orange/Blue wire terminal. Check continuity between ground and White/Blue wire terminal. If continuity exists, sensor is shorted to ground. Replace crank angle sensor. If no continuity exists, proceed to next step.
  4. Reconnect sensor connector. Attach system checker harness to main wire harness only, not to ECU. Using an ohmmeter, check resistance between connector C3 and C4 terminals. Resistance should be 650-850 ohms.
  5. If resistance is not within specification, repair open or short in Orange/Blue and/or White/Blue wire. If resistance is within specification, substitute a known good ECU. If condition is rectified, replace original 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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