One Day Your Car Won’t Pass a Smog Test. Here’s How to Prepare.

For millions of American commuters, smog checks are part of everyday life. Once your car reaches a certain age, you have to go to a station that sticks something up the tailpipe, and they either give you a yay or nay. If the answer is yay, congrats! You are good for another year or two. If it’s a nay…you will be in for costly repairs to get your car or truck back up to snuff. But what if there were a better way? A way to circumvent this process altogether? We are here to tell you that there is a way to avoid getting hassled over your catalytic converter or any other myriad problems that can and will afflict your car. 

Remember, it is not a matter of if you will fail an emissions test, but when. Exhaust gasses are the most corrosive substance on your vehicle. They are filled with nasty, caustic substances mixed with a heaping helping of high heat. Roll that together with road grime, humidity, and salt, and you have a recipe for systems failure. And you will pay for it one way or another. 

A Short History of Smog Checks

This is a misnomer; this isn’t a history of smog checks. This is more a history of what led to smog checks. 

The smog check situation began in the early ’60s with the Clean Air Act, which is nothing more than the codified statutes found in 42 U.S.C., Chapter 85. This reading is brutal, so feel free to dive in if you wish.  

The long and short of it came down to this: between the turn of the 20th Century and the early 1960s, America was experiencing the detrimental effects of air pollution on an increasingly large scale. Major smog events occurred as far back as 1948, when Donora, Pennsylvania, was enveloped in a major air pollution event that killed as many as twenty and created respiratory issues for almost half of the population of 14,000. 

The event was brutal, brought on by hydrogen fluoride and sulfur dioxide emissions from a local steel plant. 

The details of the Donora smog catastrophe are tragic and were probably avoidable. So why talk about industrial events like Donora if the issue at hand is smog checks on cars?

Because there is a direct lineage from the reaction to smog events like Donora and your car getting probed and tested for emissions annually. 

It is safe to say that we can all understand the need to reign in what happened in Donora. And this was hardly the only event to occur in steel country; the infamous Cuyahoga River fire of 1969 displayed how utterly toxic that region was because of the failure to properly dispose of materials in production. 

Talk about trickle-down bureaucracy. 

What you witness now has a direct correlation to those early catastrophes. And those can only be described as catastrophic.

But there has to be some modicum of common sense. A Civic flunking a smog check is a far cry from a noxious cloud of deadly chemicals wafting over an entire town and killing people. 

In my opinion, the Clean Air Act was a gateway drug for the federal government and the states to chip away at the average guy. Because come on, we can agree about which one was the existential threat (factories churning out deadly chemicals), and which one is window dressing (your Kawasaki 125 dirt bike on a Saturday morning). But governments never care to roll back regulations once they have been imposed.

Even if you have a different opinion, one thing’s for sure: No single system made cars and trucks more difficult to work on and less reliable than emissions.

How to Fail a Smog Check

Emissions systems have made some great designs absolute dogs. But the auto manufacturers have to comply with emissions standards, period. 

So what causes a car or truck to flunk a smog check? Usually, it comes down to a few items, but it’s certainly not limited to just a few items. The most common causes of a failed smog check are:

• Overdue oil change

• Dirty air filter

• Clogged catalytic converter

• Faulty charcoal canister

• Obstructed vent valve

• Incorrect or faulty fuel cap

The problems can be as small as dirty oil or a dirty air filter (or poor overhaul maintenance), evap system leaks, dirty or bad oxygen sensors, and especially the classic catalytic converter clogged or worn out. 

Even the most diehard shade tree mechanics can run into a brick wall chasing down emissions issues, and once you have an emission problem that causes your car to flunk the smog check, you have to get it straightened out before you can drive again (at least in California; more on that later). 

Are these fixes expensive? Oh yes, they certainly can be. With catalytic converters often costing $300-$500 for parts only, you can only imagine the final bill after taking it to a muffler shop, plus the diagnostic costs to arrive at the problem in the first place.

Can a Fuel Cap Really Fail a Smog Check?

Oddly enough, yes, a gas cap can be a contributing cause of failing a smog check. The gas cap is an important part of the evap system, and modern gas caps are designed to provide a seal so the tank operates with a certain level of vacuum pressure. If the gas cap is loose, or the sealing element is damaged or broken, it can throw codes like these: 

• P0440

• P0441

• P0442

• P0443

• P0446

• P0453

• P0455

• P0456

Another common fault is that the original gas cap was damaged and replaced with an incorrect cap. Unlike the old 1970s and 1980s cars and trucks that used universal metal caps (you can see them in your mind if you’re an ‘80s kid like me), modern gas caps are often specific to a make and model.

You should only hope that the issue is as simple as a bad gas cap, and you should absolutely start there. Also, if you happen to be throwing codes and have a check engine light, drop the $20-$50 and get yourself an OBDII checker. Trust me, it is the most valuable tool in your toolbox on cars made after 1996.

Can I Run an Emissions Test on My Own?

Luckily for you, personal automobile scanning technology has come a long way over the past decade, allowing you to preempt your local smog test with a relatively small investment of time and money.

Every car imported to the US or made in the US since 1996 is equipped with an onboard diagnostic system. Before smart devices, you could (and still can) buy a handheld diagnostic scanning tool that would read the codes and erase codes. 

Now there are a bunch of scanning tools that interface through iOS and Android apps and let me tell you, they are awesome. 

For example (this is not sponsored), the U-Scan app couples with a dedicated scanning tool to pull codes and erase codes. Also, you can graph parameters while the engine is running, and it also lets you know if you are going to pass emissions or not. 

As you can see from my 2005 Toyota Sienna, I would be failing right now if I were in a state that required testing. 

When you dig a little deeper, you can see that my car is throwing P0420 and P0430 codes, which are indicators that my catalytic converters are shot. And this app setup is extremely useful if you don’t have to worry about passing emissions. If your check engine light gets triggered, it is best to find out what it is immediately. If it is flagged for a major engine system or a transmission (which happened to me), it can keep you from getting stranded. 

What Is the Smog Check Testing For?

All internal combustion engines put out pollutants. They always have, and as long as they operate using fossil fuels, they always will. The question is how much, and what type? 

The significant toxins smog tests are looking for are:

• Carbon monoxide

• Hydrocarbon

• Carbon dioxide

• Oxygen

• Nitrogen oxide

These are the toxins (or at least a few of them) that make up the infamous greenhouse gasses. 

Which States Have the Strictest Smog Laws?

A little over half of the states have some emissions testing, and although they are all different, some are far more strict than others. 

California

It should be no surprise that Cali has some of the most strict emissions laws in the nation. They are notorious for their testing requirements, and they mean business. For one, you cannot even sell your car unless it has a passing smog check! As in, it will not be processed by the DMV even if someone offers you cash for it.   

For the first four years of a vehicle’s life, California vehicles do not have to be emissions-tested; instead, the vehicle can be waived, and a $25 abatement fee is paid to the state. What is an abatement fee? Tax with extra letters. 

The other vehicles exempt from smog checks in California are:

• Hybrids and EVs

• Gas vehicles of the model year 1975 and older

• Diesels 1997 and older

• Diesels weighing 14,000lbs or more

• Natural gas vehicles of 14,000lbs or more

• Motorcycles

• Trailers

Otherwise, all vehicles that are not exempt must be tested annually, although a few more remote areas of the state allow that to be rolled back to once every other year. 

When or if you move to California, even if you have a valid out-of-state smog check, it will not suffice, and you must get it checked in California. If required, you must have a valid passing test to register your car in California, bar none.

New York

The Empire State gives no quarter for avoiding state vehicle safety inspections, but some exemptions for emissions inspections exist. Emissions exemptions in New York apply to:

• Vehicles less than two years old

• Vehicles over 25 years old

• Electric vehicles

• Motorcycles

• Vehicles with historical plates

• Vehicles meeting heavy safety inspection standards 

• Diesel-powered vehicles made after 1997 weighing under 8,501lbs. However, this still requires an OBD II emissions test. 

Assuming you don’t fall into one of these categories, you must get your vehicle tested annually, and, of course, you need to pass, or else your car is down for the count. 

If you fail, you can conduct repairs as necessary, and the inspection only needs to cover the portion that failed if retested within 30 days. If you go over 30 days before retesting, you must redo the test. Ouch. 

You might be able to apply for a waiver if your car repairs do not fix it and it continues to fail smog checks. So, good luck with this. 

How You Can Take Matters Into Your Own Hands

Again, we aren’t insinuating that there weren’t serious environmental circumstances that needed to be addressed. Raging burning rivers and noxious, deadly fog are obvious indicators. But it could be argued that any value that could be gleaned from further regulations has long since sunsetted. 

Also, here is food for thought: if people are replacing their cars and trucks to keep them new enough to avoid emissions inspections, then we are dealing with more consumer waste. When vehicles are traded arbitrarily, it demands that another product be produced to replace it, which is exponentially more impactful to the environment than a car that busts emissions requirements.  

But what can you really do about it? In a tangible way, what can you do to circumvent some of these rules?

Move Somewhere Else

Well, for one, you can move. Of course, with over thirty states participating in some emissions checks, your odds are somewhat reduced at finding somewhere that doesn’t do emissions tests, but plenty of rural areas do not require them.

Register as a Historic Vehicle

Many states don’t require vehicles registered under historic, classic, or collector status to pass any smog inspection or emissions tests. If your vehicle is old enough to qualify as a classic in your state, this might give you the freedom to ditch your smog equipment once and for all if that’s what you’re looking to do.

Register your car somewhere else

Or, you can explore a non-traditional route. Dirt Legal offers you the ability to register your car in one of a few states that do not have any requirements for emissions tests or state inspections. And if saving a bunch on your tax bill is music to your ears, our Montana LLC Program is exactly what the doctor ordered. Not only does Montana not require emissions tests, but they also have no state sales tax.

One added benefit of our Montana LLC Program is that it provides evidence that your vehicle is owned by a resident of Montana. At first glance, you may be concerned that your local Johnny Law will be less than thrilled when you whip out that out-of-state registration and your in-state driver’s license. But if you are armed with your Montana LLC, i.e., business paperwork, you have proof of your residence in that state in which your vehicle is registered, and that your vehicle belongs to the business rather than to you, the individual. 

Dirt Legal has options to keep you on the road and out of the emissions shop, whatever way you decide to go, and whatever kind of vehicle you own. Fixes for failed emissions tests will easily get into four figures, especially with the shortage of parts that we face now. On top of that, some states (we’re looking at you, California) force you to stop using the vehicle until it passes. Look, cars connect us to our livelihood. It’s how we work, how we eat, and how we enjoy life. Take the power back from the DMV and put it back to yourself, where it belongs. You know what you need to do, and Dirt Legal allows you to do it. 

Go ahead and smash that button, get your car registered out of state, and give yourself the peace of mind of knowing you can just keep driving past that emissions shop.