I HAVE A 1999 BMW 323I,THE CHECK ENGINE LIGHT IS ON AND IT WILL NOT PASS SMOG...WHAT DO I DO??
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1999 BMW 323i Question: WON'T PASS SMOG
Answer #1patrick mannion from Greg Solow's Engine Room, June 23, 2011, 22:38Master
It must be determined why the check engine light is on. A scan tool is needed to retrieve codes stored in the memory of the computer in your car to determine what fault it saw to turn on the light in the first place. You also just can't get a fault code reader and turn of the light (in most cases the light will come back on straight away any way). The test centers look to see if certain criteria has been looked at and passed as OK by the computer in your car. If its not passed results will come back as "monitors not met" and the car will have to have the fault corrected and sufficient miles put on the car to prove to the cars computer that all is now OK. First step is get the codes read that are stored in the computer, they will look like P0302 (which would be misfire cylinder #2), P0420 ( low cat efficiency) each code gives the area in which the fault lays and what path to follow to diagnose the problem.