OBDII Reader Confusion

Hello again,

My car is due for its emissions inspection this month and I thought I’d run a readiness test with my OBDII reader before-hand to see what shape we’re in. I’m a little confused by the readings/setup on my reader. It runs through the usual checks and will say ‘Supported’ or ‘Not Supported’ but then will cycle through all the readings again and say either ‘Complete’ or ‘Not Complete’. I will have two seemingly contradictory readings for the same thing. Example: Heated Cat: Not Supported, but then says Heated Cat: Complete. I get the same differing readings for my EGR system, Catalytic Converter, Sec Air System, and AC Refrigerant. So, do I have a problem (not pass emissions) with these systems since it says Not Supported or are they ok cause it then says Complete. Note: All the other checks agree with each other, i.e., supported and complete. What does supported mean versus complete? The mini manual that came with the reader does not explain the difference. Thanks as always.

96 Saturn SL2

Cars monitor 7 or 8 readiness tests. Supported means it is a readiness test your computer monitors. Unsupported means your car doesn’t monitor that test. Complete means that test has been performed and passed. Not Complete means the computer has not run that readiness test yet.

Whenever error codes are cleared out of the computers memory, all the readiness tests are reset and read Not Complete. The car then has to be driven through a couple of “Drive Cycles” (which vary from manufacturer) for the readiness tests to Complete.

Thank you for the info. I’ve got a GM (Saturn) manufactured car, what would you say a typical drive cycle would be? Drive a few miles in town and then go on the free way a few miles? Thank you.

We don’t work on many domestic cars. I don’t know about GM drive cycles. Usually it takes 3-5 miles 30-35 mph, and 30 miles at highway speed, followed by the same 3-5 miles 30-35 mph. It can take 100 to 150 miles sometimes to get all the tests to reset. I usually tell my customers to drive for 3 or 4 days and then check the monitors.