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Home >> Nissan-Datsun >> 1997 >> Sentra Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes 1.6 >> Self-Diagnostics Using Mil >> Oxygen Sensor Monitor
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Oxygen Sensor Monitor

  1. To check if the front (4-cyl.) or left front (V6) oxygen sensor is switching between rich and lean, activate diagnostic test mode 2. See RETRIEVING CODES under SELF-DIAGNOSTICS USING MIL . Start engine while in mode 2 and run until fully warm. Run engine at 2000 RPM without load for 2 minutes, while monitoring MIL.
  2. If MIL flashes at least 5 times every 10 seconds, this indicates front oxygen sensor is functioning and fuel mixture is switching between lean and rich. This is an indication fuel mixture control system is okay.
  3. If MIL stays lit all or most of the time, a lean condition is indicated. Mixture control may be in open loop, ensure engine is fully warm. Fuel mixture may be lean or oxygen sensor may be faulty. Check for DTCs and repair if necessary. Check for conditions that could cause lean mixture, if okay, replace oxygen sensor.
  4. If MIL is off all or most of the time, a rich condition is indicated. Check for DTCs and repair as necessary. Check for conditions that could cause a rich condition, if okay, replace oxygen sensor.
  5. To monitor right front (V6) oxygen sensor after monitoring left front oxygen sensor, turn diagnostic mode selector on ECM fully clockwise. Wait 2 seconds, then turn mode selector fully counterclockwise. MIL will quickly flash twice indicating change to right oxygen sensor monitoring. To switch back to left oxygen sensor monitoring repeat procedure. MIL will flash quickly 4 times.
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