Miles before check engine light reset

[Couper1]

2 part question if anyone can help. I searched but couldn't find the answers.

#1) Can you actually "completely" reset the check engine light by disconnecting the battery? I disconnected the battery and the light went out but does that really reset the codes?

#2) Once the check engine light is reset, how many miles do you need to drive the car before it can pass inspection? I drove mine 109 miles and it did not pass the emissoins test?

Thanks for your help.

[JFP in PA]

To some degree, you are peeing into the wind here. Disconnecting the battery will clear most, but not necessarily all codes. While it will clear most emissions related codes, but if the problems are not repaired, the codes will re-trigger in a “pending” format waiting to see if the trouble persists.

Automatic clearing takes place if the code source is removed and does not return (e.g.: the car is repaired); but is dependent upon the number of cycles (cold start, full warm up, drive at speed, full cool down) more so than mileage.

This technology was instituted to prevent dumping the codes just before going to inspection; as you have found out, it works. Have the car scanned for codes, and fix the problem(s).

[Couper1]

Thanks JFP, I should have mentioned that the check engine light was triggered by the faulty air oil separator that I replaced over the winter months. There is no question the separator was bad as it was blowing white smoke EVERY time I'd start the car.
Since the repair, I never had the light properly reset so I just disconnected the battery and it went away. Hence my question if that really reset it properly. Some cars it does...not sure about the Box.

My Volvo had the same problem and I was told that 80 miles would clear it out. I've done many start/stops...highway and city driving during the 109 miles. I though that would be enough to pass the inspection but it's not.

[JFP in PA]

It is entirely possible that there is still another fault (or a third or fourth) that has yet to be identified and needs to be fixed as well. Get the car scanned, and then you will know what you are dealing with. You can buy a cheap scanner yourself for about $40-60 as well...............

[Couper1]

If any code still exists I will post it here.

But here's the question I really want to know.

Assuming there are no other repairs needed, and the light's been properly reset....how many miles do you need to drive the Boxster before it will pass an emmisions inspection?

Does anyone have experience with that?

Thanks

[JFP in PA]

Yes, I own a shop; we do this all the time. Once the car has been properly repaired, and the code(s) has been cleared, it should pass inspection immediately; no waiting or miles are required.

[thstone]

+1 JFP - excellent reply.

Check for codes again and post them here...