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Home >> Infiniti >> 1994 >> Q45 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Fuel System >> Fuel Control >> Feedback System
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Feedback System

  1. Start engine, and warm it to operating temperature. Ensure idle speed and timing are adjusted to specification. Increase engine speed to about 2000 RPM for 2 minutes under no-load condition. Using a small screwdriver, turn diagnostic mode selector screw on ECM.
  2. With mode selector screw turned fully clockwise for at least 2 seconds, inspection lights will begin to flash. Turn screw fully counterclockwise. This switches ECM to Mode II, which is used to monitor exhaust gas sensor feedback signals.
  3. With engine speed at 2000 RPM for 2 minutes, LED should flash at least 5 times during a 10-second period. If sensor does not respond as indicated and no other faults which may affect air/fuel mixture are indicated by ECM self-diagnostic system, use a voltmeter to verify input signals to ECM are correct. If input signals are correct, replace oxygen sensor. If input signals are not correct, replace ECM.
  4. Vehicle uses 2 oxygen sensors. When Mode II is first entered, left bank oxygen sensor is being monitored. To change to right bank monitoring (with engine running), turn diagnostic mode selector screw on ECM fully clockwise. Wait at least 2 seconds. Turn selector lever fully counterclockwise. Repeat step 2).
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