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Home >> Honda >> 1987 >> Prelude Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI Electronic Control System >> Testing >> Code 9, CYL Sensor
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Code 9, CYL Sensor

  1. Turn off ignition. Remove clock 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 2-wire sensor connector. Measure resistance across sensor terminals. If reading is not 700-1000 ohms, replace CYL sensor assembly. If reading is within specification, proceed to next step.
  3. Check continuity between ground and each sensor terminal. If continuity exists, replace CYL sensor assembly. If no continuity exists, proceed to next step.
  4. Reconnect sensor connector. Attach system checker harness to main wire harness only, not to ECU. Check resistance between connector terminals C1 and C2. Resistance should be 700-1000 ohms.
  5. If resistance is not within specification, repair open in Orange and/or White wires. If resistance is within specification, substitute a known good ECU. If condition is rectified, replace original ECU.
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