How many miles do you get before you have trouble passing emissions?

I think everyone's idea of what constitutes an emissions test is different. Using the google machine, it appears 34 States require vehicle emissions testing.

Of the 34, I have no idea if any still do a tailpipe emissions test. I live in a PZEV State and we don't do them. Never did as far as I know.

It would be interesting to know how long a OBDII compliant vehicle could pass a tailpipe emissions test, given it's running as designed, with no MIL on, no codes, etc.

I can tell you what is needed in Belgium: For a gas enfine there's a sniffer placed up the tailpipe and it measures O2, Co, CO2, HC and displays lambda. CO has a max limit (0.5% i would think) and Lambda has to be between 0.97 an 1.03. Some cars get tested at idle others at 2500 rpm, depends on the year of manufacture.

If the car smokes excessively they can fail it for that even if you pass the sniffer test.
 
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My "check engine" light is normally on. If I disconnect the battery it goes off for about 100 miles. They won't test the car with that light on. So the last two times I had testing, I disconnected the battery before testing and passed it.
In case you are wondering, I'm not putting money into a "check engine" light error on a > 200k mile car when my MPG has actually gone up a little since the light came on ;) (and yes, I keep track of that too).
 
My "check engine" light is normally on. If I disconnect the battery it goes off for about 100 miles. They won't test the car with that light on. So the last two times I had testing, I disconnected the battery before testing and passed it.
In case you are wondering, I'm not putting money into a "check engine" light error on a > 200k mile car when my MPG has actually gone up a little since the light came on ;) (and yes, I keep track of that too).
That won’t work here in Southeastern Wisconsin. The presence of just the light isn’t the determining factor. All of the appropriate flags in the computer have to be ready.
 
Two trucks ago I had a '97 4.6 F150. The check engine light came on twice in 340,000 miles ( plugged EGR passage, O2 sensor heater). It burned a quart of oil every 1000ish miles. I added over 150 qts of oil, and it never set converter efficiency O2 sensor performance codes. My wife had a 3.9 Lincoln LS with 200,000 miles. That CE light came on probably 15 times. In the rare instance it went off, I'd send her right to the OBD port test center. It just depends on the make and model. Some engines are more misfire prone than others and misfires seem to be the quickest way to destroy the converter/s.
 
Never failed, but my 12 Accent had fuel trim and ecu issues, I drove it so much by the time they figured it was acting up, I had 199930 miles on it. Got two grand from Honda sight unseen and bought the R18 2015 Civic with 11 miles on it in January 2016 til died at 382500 in December of 20'.
 
If you take care of 'em...shouldn't have any issues. I had a '96 4runner that we sold with about 300K on it and never an issue passing smog in CA. 2003 4runner had a botched headgasket job when I bought it that took out a cat (or contributed to its early demise)...changed it and no issues, then the light came back on throwing a code for the other cat. I'm not sure how the ECM monitors cat efficiency, but I suspect it was watching both degrade equally up until a point (at 190K miles) and then when the new one went on....that one worked obviously like new and the efficiency differential between the left and right was too great maybe?...so I put the other new cat on and it did fine for another 4 years till we sold it with 250Kish miles on it.

Dad's 77 GMC motorhome stinks to high hell but passes every year.

If it's working mostly right, it'll pass.
 
Dad's 77 GMC motorhome stinks to high hell but passes every year.
The limits change, year to year, of manufacture. A 1977 model would be allowed to pollute more than a 2007. It's only required to meet the requirements of the year of it's manufacture.

And it's very likely that a 1977 motorhome would have very high limits if any at all (might not have had limits if it was above a certain GVWR).
 
The limits change, year to year, of manufacture. A 1977 model would be allowed to pollute more than a 2007. It's only required to meet the requirements of the year of it's manufacture.

And it's very likely that a 1977 motorhome would have very high limits if any at all (might not have had limits if it was above a certain GVWR).
It's usually safety only after 25 years. Guess not in California.
 
Never failed, but my 12 Accent had fuel trim and ecu issues, I drove it so much by the time they figured it was acting up, I had 199930 miles on it. Got two grand from Honda sight unseen and bought the R18 2015 Civic with 11 miles on it in January 2016 til died at 382500 in December of 20'.
Just reached 382500 on my 2017 Honda Accord Sport 2.4 today!

20250318_153950.webp
 
My 2016 8th gen Malibu 2.5L just started throwing a P0420 catalyst inefficiency code at 97700 miles. Runs like a top otherwise. I'm due for my yearly state inspection this month and it won't pass with this code. :(
 
A number of posts mention Evap codes causing failure to pass OBD II emission checks. What is not widely known is that Evap is the hardest monitor to set, and in most places (Federal rules that most states follow) the monitor doesn't need to be set, it just can't be in a fail condition.
The Evap check won't run unless the gas tank is between 1/4 and 3/4 full, and a number of other conditions are met. If you are having trouble passing emission checks because of an Evap code, you can just reset all the DTC codes with a cheap OBD II reader, drive a couple of drive cycles to allow the other monitors to complete their checks, use the reader to check all are set except for Evap, then take it for the emission check.
If for some reason the Evap fails before you can get the emission test completed, just fill the gas tank and repeat. The Evap test won't run (and thus fail) until 1/4th of the gas tank is burned.
 
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