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Home >> Oldsmobile >> 1987 >> Calais Base, 4D Sedan, 2.5 U, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> 2.3L VIN [D] CEC Tests W/Codes >> Diagnostic Code Flow Charts (Code Charts) >> Code 45 - Rich Oxygen Sensor Value >> Notes

Code 45 - Rich Oxygen Sensor Value: Notes

About .45 volt is supplied by ECM between terminals "YC14" and "YC15" (if measured with 10 megohm digital voltmeter, reading may be as low as .32 volt). The O2 sensor varies voltage within a range of .10-1 volt (from lean to rich). The O2 sensor operates like an open circuit, producing no voltage when temperature is below 600°F (316°C). ECM operates in "open loop" until temperature exceeds given value.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. The following conditions must be met to set a Code 45:
    • O2 sensor voltage is greater than .75 volt.
    • No Code 33 or 34.
    • Fuel system in "closed loop".
    • TPS greater than 5 percent.
    • Above conditions met for 50 seconds.
  2. This test checks for faulty connections to ECM.
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