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Confirmation Test (Using Oscilloscope)

  1. Access ECM at left front of engine compartment. Test bank No. 1 and 2 oxygen sensors No. 1. Backprobing, connect oscilloscope between ECM E3 connector terminal No. 12 (White wire), ECM E3 connector terminal No. 11 (Black wire) and ECM E3 connector terminal No. 17 (Brown wire). Test banks No. 1 and 2 oxygen sensors No. 2. Backprobing, connect oscilloscope, between ECM E5 connector terminal No. 18 (White wire), ECM E5 connector terminal No. 27 (Red wire) and ECM E3 connector terminal No. 17 (Brown wire).
  2. Ensure all accessories are turned off. Start and warm engine to normal operating temperature. Increase engine speed to 2500-3000 RPM for 3 minutes. Using oscilloscope, ensure heated oxygen sensors (bank 1 and 2 sensor 1 and 2) feedback to ECM fluctuates around .5 volt. See Figure.
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