How do I pass inspection in Texas with a check engine light (clearing codes)?


I’m getting a P0420 code due to oil burning and leaking which is causing issues with the catalytic converter.

Someone told me that I should clear the code, drive 60 miles, and then get the inspection done. They said that if the code stays off, I should be able to pass.

Do you think this is true?
Why is it important to drive 60 miles after clearing the code?

Thank you.

Edit: the engine is both leaking and burning oil.

The inspection station can tell if the code was recently cleared. They will have you come back later. They do not want someone to clear the codes just as you pull into the shop. Have you tried Restore in the oil. That might help reduce the oil burning.

The purpose of the inspection is to take oil burning polluting cars off the road. If that is your car and you can’t afford to fix it or get another car you are in a tough position


If there’s a problem with the catalytic converter where a P0420 DTC is set, the code will return in a short time.

Also when you erase any codes, the readiness monitors will reset. This will cause the vehicle to fail the emission test right then and there.

It’s best to repair the vehicle so the code doesn’t return.



I plan on using Restore soon. Do you think it can take away the code?

Driving 60 miles after clearing the code will still show the readiness monitors as being reset?

The readiness monitors won’t reset until the vehicle is put through a drive cycle.

That means the vehicle has to be driven under certain conditions so the readiness monitors will reset.

And sometimes it takes a number of drive cycles to accomplish this.



No. That code indicates a high likelihood that the catalytic converter needs to be replaced. Stopping the engine from burning oil won’t reverse that but it will protect the new cat.

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60 miles isn’t considered a drive cycle? What did a drive cycle consist of?


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Wow. That is very helpful. Thanks. My camry is a 2005 though. A drive cycle may be a little different for this car. I will do a google search.

People make these numbers up. Some say 50 miles, others say 75 miles.

I can usually get all monitors except the evaporative emission monitor to pass in 5 miles. Evaporative emission monitor is only tested during a cold start but usually you are allowed one incomplete monitor.

If your catalytic converter is failing, the catalyst monitor may not pass.


Thanks. Any recommendations for getting it mine pass after approx 5 miles? My CEL is less likelynto come back on with that amount of mileage.

You can’t fool the emission testing station.

Either repair the car so it’ll pass the emission test, or junk it.



Turning off a diagnostic code using a code reader may also reset the corresponding readiness monitor, which may cause an automatic emissions testing failure. However some readiness monitors are allowed to have the reset state and still pass. Your Texas DMV seems to have much difficulty in providing clarity, but you might be able to glean something helpful here:,their%20Ready%2FNot%20Ready%20status


As already mentioned, you can have one monitor incomplete in Texas and still pass. The EVAP monitor generally only runs on a cold start with between 1/4 and 3/4 of a tank of gas. If it doesn’t set, there is probably no point in attempting a drive cycle as the Catalyst monitor will likely fail. Most vehicles will complete a drive cycle quickly on a road that allows for 45-50 mph cruising and some stop lights.

I am going to go way, way, way against the grain here. I have long felt that the way emissions testing is implemented, it is less about protecting the environment and more about punishing poor people for being poor. If the goal was to reduce pollution, then every car–regardless of model year–should be tested by exhaust gas analysis, and the presence or absence of any warning lights or trouble codes should be immaterial. This is how 1995 and older vehicles are tested, and is the fairest method of testing for emissions compliance.

The idea that 1996 or newer vehicles can only pass emissions testing if the check engine light is off, and no trouble codes are stored, and the required number of monitors are set to “ready” is really capricious and unreasonable, as many trouble codes result in little to no additional pollution–but your car still fails regardless. Many perfectly good cars end up junked because the owner cannot afford to sink vast sums of money into chasing electrical gremlins, especially when it comes to EVAP codes, etc. Similarly, I see many cars on the road which are visibly polluting based on the amount of oil being burned, yet these people were able to get through emissions (or have a friend/family member willing to let them use their address in a non-emission testing county to avoid testing at all).

Because of the fact that I think emissions testing based solely on OBDII trouble codes is a scam, I would spend no money trying to fix a problem that is not affecting drivability and that I do not believe is creating excessive pollution. Instead, I would attempt to bypass the problem, either by figuring out how to prevent the PCM from running the monitor which generates the trouble code, or by figuring out what data the PCM needs to see, and how to simulate it in order to avoid setting trouble code(s).

For example, I have a car which thinks there is a small leak in the EVAP system, which no one has ever been able to find. If all of the monitors are allowed to run, it will set codes P0442 and P0456. Yet I have driven the car many thousands of miles with the CEL illuminated, and it runs fine. When it’s time for emissions testing, I know to disconnect the battery, clear the codes, and how to prevent the EVAP monitor from running long enough to get the car through emissions. However, someone else who did not have this knowledge would be forced to either spend hundreds (maybe even thousands) of dollars trying to fix the problem, junk the car, or drive it illegally with expired tags.

If I was in the position of the OP, and could not afford to repair/replace the engine and catalytic converter(s), I would look into how to fool the PCM into not seeing that the catalyst efficiency is low. For many cars, there are O2 sensor simulators, or O2 sensor extension tubes which will prevent the PCM from setting a catalyst efficiency code. A Google search should give more information on how to obtain and install such devices.


Isn’t there some kind of clause that says if you spend a modest amount of money and a good faith effort to resolve the problem, then they will pass you anyway?

I recall something along those lines in my state, but similar statutes might not exist in every state.

These do work. Just search “o2 sensor spark plug non fouler”.
Just realize that it’s against federal law to tamper with your vehicle’s emission systems.

There will always be those who will resort to tampering with their car’s emissions so that they can get to work, keep their job, and keep their family fed. I am in no position to judge them.


I wonder which is cheaper?

Repair the vehicle so it passes the emission test, or follow the advice from hacks and get caught tampering with the emission components and pay a $20,000 fine to the EPA, and pay whatever fine the state decides to impose?