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itzed 12-09-2012 06:17 AM

Emissions test question
Hi. 2006 NA 2.5i. My state, Maryland, does OBDII testing and I'm due. Recently, the CE light came on and threw the P0420 code for O2 or cat problem. However, it went out after about two tanks of gas, came back on for short while again, and then went off again. It's currently off, and has been off for about 1000 miles. During this last time of being off, I have switched to mid grade gas, and have noticed a considerable improvement in low end torque and drivability, basically can't believe the difference it has made. The car is running great, and I'm real hopeful the light will stay off. Anyway, my question is, does the OBD II need to be cleared and reset, or will the car pass emissions since the light is currently off? I'd like to go ASAP and get it done while its off and not have to worry about it for two years, if I have to clear the codes, I will need to drive around for a good while before I can take it for the test. Thanks.

Burba88 12-09-2012 07:33 AM

You will be fine as long as the CEL is not on your good to go

BAC5.2 12-09-2012 07:36 AM


Originally Posted by Burba88 (Post 4193229)
You will be fine as long as the CEL is not on your good to go


If the readiness codes are not set, they will fail the car even if the CEL is not currently on.

Reset the ECU to clear all of the readiness codes and CEL history, drive the car for a little while, and if the CEL stays off then you are good to go.

Burba88 12-09-2012 08:57 AM

Guess we learn something new every day.

1055 12-09-2012 09:23 AM

If the code goes off on its own the monitor will still be set, allowing you to pass..

itzed 12-09-2012 06:14 PM


Originally Posted by 1055 (Post 4193355)
If the code goes off on its own the monitor will still be set, allowing you to pass..

This is what I was hoping, and seems logical. I hope you are correct. Just got the notice yesterday, might head there tomorrow and keep my fingers crossed.

Burba88 12-09-2012 06:30 PM

let us know.

itzed 12-10-2012 04:46 AM

Crap! I can't believe my bad luck. The light has been off for over 1000 miles now, so my notice arrived Saturday and I put it in the car this morning, planning to go to the emissions test at lunch. Then on the way to work this morning the freakin CEL comes on again. I guess I'll have to replace the rear O2 sensor, reset the light, and take it from there. I was 10 miles from getting this done.

itzed 12-21-2012 07:36 PM

Here's an update for future searchers. I passed the emissions test today, although I'm not sure how. Using the Torque app on my droid phone and a Bluetooth OBDII interface I bought on eBay, I cleared the code about a thousand miles ago. I kept track of the IM readiness and most of the tests were completed fairly quickly, but the following kept showing not ready: Reserved; Heated Catalyst; and A/C Refrigerant. Having done a good bit of research on the web, I assumed that it would not pass based on the Heated Catalyst test not being ready, and at least one article written by the Maryland emissions people themselves said that a faulty sensor could keep the test from actually running. So I bought a new rear O2 sensor on Amazon. Today I figured I had nothing to lose by taking it to the test first, and maybe in their last day before Christmas, they would have mercy on me and give me a gift of passing. :lol: Well, I made some good conversation with the tester during the whole process, and low and behold, it passed. I have no idea if it was a Christmas gift, or if Maryland doesn't care about the heated catalyst test, or if my Torque software is reading it incorrectly (I doubt it). But whatever, the light has not come back on since I cleared it, and I'm good for another two years as far as Maryland is concerned.

cseagle08 12-21-2012 08:47 PM

MD emissions were such a joke when I lived there.

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