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Oxygen Sensor

  1. Operate engine until engine oil temperature is at a minimum of 176°F (80°C). Check for leaks in exhaust system. Using Adapter (Sun 120 239 ), connect CO test equipment hose to the sampling point on left exhaust pipe.
  2. Allow engine to idle for approximately 2 minutes and note CO reading. Remove hose from pressure regulator and pinch closed. This is done to check function of oxygen regulation. CO reading should increase briefly and then drop again.
  3. If reading did not increase then drop, disconnect connector at oxygen sensor. DO NOT allow oxygen sensor wire to touch ground. Hold control wire to ground. CO reading should increase. Connect control unit wire connector to alternator connector. CO reading should decrease.
  4. If CO reading was incorrect, check wire connection on control unit. See TESTING in this section. If wiring connection is okay, replace control unit. Oxygen sensor is defective if test step 2) was faulty, but test step 3) was okay. Replace oxygen sensor.
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