meier motor sports Posted October 10, 2007 Share Posted October 10, 2007 The ODBII and newer uses a datalogger in the ECU for emissions. If you only drive it 2-3 minutes at a time, then there is no valid data in the log, so it fails your emissions. Go drive for 15 minutes, and it gets a valid log, and then you pass. right and wrong. its called a drive cycle. its not a predetermined time but the car does need to go through predefined settings to meet a drive cycle. like start coolant needs to raise a certain amount and stay between a certain part. you need to coast a certain amount and cruise a certain amount. for fuel related monitors, fuel needs to be within a certain level. etc etc etc. and then you need a certain number of drive cycles to pass all obd2 checks. and the reason they use obd2 only now and no longer use the sniffer is because if something is wrong with the car, the car knows it. if your gas cap leaks, it can see that there is no vapor pressure within the evap system. when it trys to purge that, it sees that there is no flow. if your o2 sensors get goofy readings it can tell if your running rich lean misfiring or if you have an inoperative cat. etc etc stage 2 AP turns off some of these monitors so instead of getting in incomplete of fail you get a "not requested" and you can pass the test;) Link to comment Share on other sites More sharing options...
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