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Home >> Infiniti >> 1992 >> Q45 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostic System >> Entering Self-Diagnostics
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Entering Self-Diagnostics

  1. Turn ignition on, but leave engine off. Using a small screwdriver, turn diagnostic mode selector on ECU fully clockwise. Wait at least 2 seconds, and then turn diagnostic mode selector fully counterclockwise. Mode II self-diagnostics will result and CHECK ENGINE light and Red LED inspection light will flash codes (if present).
  2. If engine is started at this stage, CHECK ENGINE light and Red LED inspection light will display condition of air/fuel mixture, monitored by O2 sensor, whether system is in closed or open loop.
NOTE: Turn back diagnostic mode selector to fully counterclockwise position whenever vehicle is in use. Switching modes is not possible when engine is running.
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