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this code means the engine is running rich,,maybe the fuel pressure is hi or you may have a bad ect sensor[engine coolant tempeture]this is located on the front top of the intake manifold..also,if it hasn't had a tune up in a while,this will make this code show,because it isn't burning the fuel correctly
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Oxygen Sensor Circuit Code 45
Oxygen Sensor Circuit
Circuit Description: The ECM supplies a voltage of about .45 volt between terminals "D6" and "D7". (If measured with a 10 megohm digital voltmeter, this may read as low as .32 volt.) The Oxygen (02) sensor varies the voltage within a range of about 1 volt if the exhaust is rich, down through about .10 volt if exhaust is lean.The sensor is like an open circuit and produces no voltage when it is below about 315°C (600°F). An open sensor circuit or cold sensor causes "Open Loop" operation.Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.
Diagnostic Aids: Using the "Scan," observe the block learn values at different rpm and air flow conditions to determine when the Code 45 may have been set. If the conditions for Code 45 exist, the block learn values will be around 115. Code 45 will be a hard code on 4.3L CPI engine. The "SES" light will remain "ON" until the ignition is turned "OFF," due to possible high fuel pressure.An oxygen supply inside the 02 sensor is necessary for proper 02 sensor operation. This supply of oxygen is supplied through the 02 sensor wires. All 02 sensor wires and connections should be inspected for breaks or contamination that could prevent reference oxygen from reaching the 02 sensor.