How to Pass an Emissions Test
Nobody wants to fail an emissions or smog test: it means you have to figure out what caused the failure and get it fixed. Then you have to return for a re-test.
Smog tests are required by most states before a registration renewal. Requirements vary by state: in some states you have to pass a test on a yearly basis, others may require a test every two years. Still other states may require the car to be a certain age before a test is needed. You can verify your state requirements at the local DMV.
Smog or emissions testing was introduced in the 1970s when the Clean Air Act went into effect. Smog checks verify that a vehicle’s emissions system is working properly and the vehicle is not pushing pollutants into the air.
If you are concerned that your vehicle may not pass its next smog test, there are steps you can take to increase the odds of a passing grade. Following are a few tips for making sure your vehicle gets a clean bill of health at the next smog test.
Part 1 of 1: Getting your vehicle ready for an emissions test
Step 1: Clear the Check Engine Light if it is on. The Check Engine Light is almost entirely related to your emissions system.
If this particular warning light is on you will need to the get the vehicle inspected and repaired before taking it in for a smog test. In almost all circumstances, the vehicle will fail if the Check Engine Light is illuminated.
One of the most common reasons that the Check Engine Light will come on is a failing oxygen sensor. The oxygen sensor monitors the gas/air mixture being sent into the fuel injectors so the mixture can be adjusted if it is running rich or lean. A failing oxygen sensor will cause a smog check failure.
Replacing an oxygen sensor is a relatively affordable repair. Ignoring an oxygen sensor failure can lead to catalytic converter damage which is a very expensive repair.
The takeaway here is to repair any issues related to the Check Engine Light before heading to the smog test.
Step 2: Drive the vehicle. The car should be driven at highway speed for roughly two weeks before taking it in for a smog test.
Driving at higher speeds will heat up the catalytic converter enough to burn out oil and gas residues. The catalytic converter converts harmful emissions before they exit out the tailpipe.
City driving doesn’t let the converter get hot enough to completely do its job, so taking it out on the highway will burn off the gas and oil residue in the converter. This will help the vehicle pass the smog test.
Step 3: Have the oil changed before the smog test. While this will not guarantee a passing result, dirty oil can release additional pollutants.
Step 4: Have the vehicle tuned up about two weeks before the test. Have all filters changed and ask the mechanic to inspect all hoses to make sure there are no cracks or breaks.
- Note: In many cases, a mechanic will disconnect the battery while performing a tune-up, which will reset the vehicle’s computer. The vehicle then needs to be driven for a couple of weeks so there is enough diagnostic data for the smog test.
Step 5: Check the tires to make sure they are properly inflated. Most states will run a dynamometer test on the vehicle, which puts the vehicle tires on rollers so the engine can run at high speeds without moving.
Under-inflated tires will make the engine work harder and could affect your results.
Step 6: Inspect your gas cap. The gas cap seals the fuel system, and if it is cracked or not fitted properly, it will trigger the Check Engine Light.This will cause your vehicle to fail the smog test. If the cap is damaged, replace it before the test.
Step 7: Consider using a fuel additive, which can help lower emission levels. Fuel additives are usually poured directly into the gas tank when filling up the car.
Additives clean out the carbon deposits that build up in the intake and exhaust system. This can also help the vehicle pass the smog test.
Step 8: Take your car in for a pre-test. In some states, smog check stations will do a pre-test.
These tests check the emissions system just like the standard test, but the results are not recorded with the DMV. This is a surefire way to verify if your vehicle will pass.
While there is a charge for a pre-test, if you have serious doubts about your car’s chances of passing doing a pre-test is highly advised. This way you can get the car repaired before doing the official test.
Step 9: Drive the vehicle at highway speeds for at least 20 minutes before you arrive at the smog test station. This will warm the vehicle up and make sure it is running properly. It also warms up the combustion and emission system before the test.
Step 10: Have any issues fixed by a licensed mechanic if your vehicle fails to pass the emissions test. Our experienced mobile mechanics would be happy to come out to your home or office to do the necessary repairs or adjustments to make sure you pass the smog test the second time around. If you take the time to make sure your vehicle is prepared for an emissions test, you won’t have to deal with the anxiety and potential embarrassment – not to mention the inconvenience – of failing the test. Hopefully with the steps listed above, you will be able to get your vehicle ready to pass the emissions test with no problem.
Car Smog Test
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Is it Possible to Pass a Smog Check with the Check Engine Light On?
If you’ve ever faced the nerve-wracking experience of a smog check with your check engine light illuminated, you’re not alone. It’s a situation that leaves many vehicle owners anxious, wondering if they’ll pass the test. In this blog post, we’ll explore the complex relationship between the check engine light and smog checks, shedding light on whether it’s possible to pass a smog check with that ominous warning indicator on.
Understanding the Check Engine Light
The check engine light, often symbolized by a small engine icon, serves as a vehicle’s early warning system. It illuminates when the onboard computer detects a problem related to the emissions system, engine performance, or other critical components. These issues can range from minor sensor malfunctions to more significant problems with the engine or exhaust.
The Role of the Check Engine Light in Smog Checks
When it comes to smog checks, the check engine light plays a pivotal role. The presence of an illuminated check engine light typically results in an automatic smog check failure. The reason is straightforward: the check engine light indicates that there’s an emissions-related problem within the vehicle.
Emissions tests are designed to ensure that vehicles meet specific environmental standards, and the check engine light directly relates to this goal. When the light is on, it signifies that the vehicle’s emissions control systems may not be functioning optimally, potentially leading to increased emissions.
Is it Ever Possible to Pass a Smog Check with the Check Engine Light On?
In most cases, the check engine light being on will lead to a smog check failure. However, there are exceptions in certain states and under specific conditions. Some states may allow for a limited number of “not ready” monitors in the emissions system. If your check engine light is on due to a recent repair or if certain emissions monitors are not ready, you might still pass the smog check.
Addressing the Check Engine Light
The best approach to ensure you pass a smog check is to address the issue that triggered the check engine light. Here are some steps to consider:
- Diagnostic Scan: Visit a qualified mechanic or smog check station to perform a diagnostic scan and identify the specific issue causing the check engine light.
- Repairs: Once the problem is diagnosed, proceed with the necessary repairs or maintenance to resolve the issue.
- Clearing Codes: After repairs, the mechanic can clear the trouble codes and reset the check engine light.
- Drive Cycles: Drive the vehicle for a specified number of miles to complete the emissions system drive cycles, ensuring all monitors are “ready” for the smog check.
In most cases, it’s not possible to pass a smog check with the check engine light on. However, addressing the underlying issue and ensuring that all emissions monitors are “ready” can help you avoid smog check failures. When in doubt, consult a trusted smog check station like AB Smog Check in Monterey for expert guidance and assistance in passing your smog check with flying colors. Don’t let that check engine light keep you from a successful smog check; take action, resolve the issue, and drive with confidence.
Remember, regular vehicle maintenance and timely repairs can help you avoid stressful situations at smog check time and contribute to cleaner air and a healthier environment.
Disclaimer: Smog check regulations may vary by state. Always consult your local DMV or smog check authority for the most accurate and up-to-date information regarding smog check requirements.
Can You Pass a Car Inspection With The Check Engine Light On?
The dreaded check engine light (CEL) is hard to ignore. Here, our car expert explains what effect a lit CEL can have on inspection results.
Technically, no, your vehicle cannot pass an emissions inspection if the check engine light (CEL) remains on during the test. The real answer? It depends on your state and county motor vehicle laws, your vehicle’s age, gross weight and how many miles it’s been driven since its last inspection
According to Jon Stull, a certified vehicle emissions and safety instructor in Pennsylvania, even if a vehicle in his state passes a safety inspection, it’s illegal to affix a safety inspection sticker to the windshield if the vehicle fails an emissions test. He adds this is “one of the most difficult regulations to explain.”
What Is a Car Inspection?
Vehicle inspections are regulated by individual states, with most requiring two types:
- Safety inspections: These include brakes, steering and suspension, tires, exhaust, lights, etc. It ensures a vehicle is roadworthy and safe to operate.
- Emission inspections: This determines if the emission control systems are operating properly, with tailpipe emissions measured for excess smog levels. Emission inspections are performed to reduce harmful exhaust greenhouse gases.
Inspection requirements differ by state. Some require both inspections; others require only one, or none. Some states demand vehicles pass a safety and emission inspection before they can be registered. Others require proof of insurance before the inspection.
Before insuring a vehicle, some insurance companies may insist on pre-purchase inspections to identify potential problems, especially with older vehicles or salvaged flood cars. Check with your state Department of Motor Vehicles (DMV) to determine which, if any, inspections are required.
Note: For peace of mind, always get an independent pre-purchase safety and emission inspection before buying a used car.
Who Does Emission Inspections?
It depends on the state. New York and Pennsylvania certify independent repair shops and mechanics to perform emission inspections and repairs. Arizona runs its own emission testing stations. Check with your state DMV to determine where to go and who can perform an emissions inspection.
What Happens During an Emission Inspection?
Depending on the state, region and vehicle year, an emissions inspection and maintenance inspection (I/M) may include visual anti-tampering, onboard diagnostic (OBD) and/or tailpipe idle tests.
During the anti-tampering inspection, a visual examination ensures all emission components are in place, working and have not been altered. Depending on the state, inspectors check the following items:
- Catalytic converter;
- Exhaust gas recirculation (EGR) valve/system;
- Positive crankcase ventilation (PCV) valve/system;
- The air pump, its valves, pulleys and fan belts.
- Evaporative control system canister, canister filter/system;
- Fuel lines and gas cap.
During an OBD test, your vehicle will link to the emission testing equipment via the on-board diagnostic link connector (DLC). It checks:
- Readiness monitor status (the emission system’s self-test, self-diagnostic system), ensuring the OBD system is functioning properly.
- The CEL is on with the engine off and key on, and is off while the engine is running.
- The OBD system for diagnostic trouble codes (DTC).
Exhaust gases measured during the tailpipe idle test:
- Hydrocarbons (HC);
- Carbon monoxide (CO);
- Oxides of nitrogen (NOX);
- Oxygen (O2).
On average, an emissions test should take between 15 and 30 minutes.
When a vehicle fails an I/M test, the inspector issues a report. Unless the inspector is a state-certified I/M repair technician, they aren’t obligated to diagnose or suggest what repairs are necessary to pass the inspection. Otherwise, your mechanic (or you!) will need to determine why the vehicle failed the emissions inspection.
Anyone, including the vehicle owner, can make the repairs.
Is an Illuminated Check Engine Light an Automatic Fail?
Yes. The OBD test on 1996 or newer models verifies proper CEL function. If the CEL is on with the engine running, it automatically fails an emissions inspection.
However, there are exceptions, exemptions and waivers to every rule. Depending on the state, these could include:
- Vehicles older than 20 years old;
- Senior citizens with vehicles 10 years or older;
- Number of miles driven since the last emissions inspection;
- Non-traditional vehicles like classic cars, antiques and parade vehicles;
- Making and documenting repairs trying to correct the problem. You can request a one-year waiver if the vehicle fails a second time.
- Reinspected, failing the OBD test again, but passing safety inspection.
- Vehicles less than four years old (depending on the state) can pay a smog abatement fee.
Again, check with your state DMV to determine if your vehicle may be eligible for an exemption or waiver.
What To Do if Your Check Engine Light Is On
There are several easy DIY steps you can attempt to turn off the CEL.
First, make sure the gas cap is tight. You can also try disconnecting the battery for five minutes. An inexpensive code reader/scan tool may also turn the CEL off.
Is it Possible to Pass a Smog Check with the Check Engine Light On?
Can You Pass a Car Inspection With The Check Engine Light On?
