What Common Issues Cause Your Car To Fail an Inspection

Every car will have to go through an inspection at some point. As a vehicle owner understanding the problems that can come up during an inspection and cause your car to fail will help you avoid repeat inspections. This article, What Common Issues Cause Your Car To Fail an Inspection, will help you understand what to look for before an inspection. Keep reading to answer the question, what are the most popular reasons a car fails an inspection?




Inspections are an inevitable part of car ownership. There are several issues that can cause a car to fail an inspection.

  • Vehicles require regular inspection to check emissions, and safety factors.
  • Popular events that require a car inspection are, buying or selling of a vehicle, change of title, state mandated inspection, and general maintenance.
  • Different states and countries have their own set of rules governing what will meet inspection standards, and when an inspection is required.
  • Cars can fail an exam for reasons ranging from simple fixes, like replacing windshield wipers, to more complex issues like malfunctioning catalytic converters. Different reasons for failing an inspection can range in price. Some fixes will cost as little as $20, while others can cost $500-$800.
  • Inspections can be done at most local mechanic or autobody shops. On average the cost of an inspection is $60.

Continue reading to learn the ins and outs of a car inspection, what to look for prior to an inspection, and how to deal with your inspection results.

What Are the Most Common Vehicle Problems During a Car Inspection?

Car inspections are a normal part of vehicle ownership. Being aware of the most common reasons your car might fail an inspection prior to taking it in can help you pass. Here are 17 reasons your car might fail an inspection.

1. Catalytic Converters

There are two pipes that make up the catalytic converters, one for breaking down the pollutants into exhaust, and one for expelling them. The catalytic converters are responsible for transforming the pollutants into steam. If the catalytic converters are not functioning properly a vehicle will fail an exam.

2. Blocked Air Filters

The role of the air filter is to catch all of the debris that enters the hood of the car. If the air filter becomes overwhelmed with dirt and grime the engines performance will suffer.

How the air filter is maintained will directly impact how smoothly the vehicle runs. A dirty air filter can also lead to high levels of heavy metals and hydrocarbons circulating through the vehicle.

3. Engine Oil

One of the most important elements of a car, which passing an exam is contingent on, is the engine oil. Dirty oil will cause friction between car parts, which can be very damaging. Unclean oil can lead to larger problems if it is not addressed.

4. Check Engine Light

Another common reason a car might fail its inspection is because the check engine light is turned on. Often this light comes on for minor reasons, such as faulty gas cap; however, the check engine light could also indicate a more serious problem like the engine misfiring.

5. Broken Headlights or Taillights

A vehicle with broken headlights or taillights is an easy fix, but if left unattended this will result in a failed inspection. If the light is out in your headlight; you can simply change the bulb at home by removing the light plate. If the glass is broken you may want to have your vehicle serviced at an automotive shop.

6. Tail Pipe Test

Failing a tail pipe test means failing an inspection. There are several underlying causes that can lead to a car failing a tail pipe test including, the fuel and air mixture are incorrect, there is a vacuum leak, one or more broken sparkplugs, the PCV or EGR are malfunctioning, the ignition timing is off, and the oxygen sensor is malfunctioning. The solution for this issue will be costly, ranging from $200-$500.

7. Problems with the Gas Cap

A leaky, lost, or non-removable gas cap will result in a failed vehicle inspection, because it can pose a fire hazard. To repair a gas cap, usually the cap simply needs to be replaced. The gas cap on a vehicle wears out overtime and should be regularly checked.

8. Air to Fuel Ratio

The correct air to fuel ratio is 1-part fuel to 14.7 parts air. When this ratio is off the fuel cannot combust properly, which raises safety concerns. There are a few different reasons the air to fuel ratio in your vehicle can be wrong, and the issue should be addressed by a professional.

9. Broken or Worn Out Spark Plugs

The spark plugs are in charge of igniting the fuel in your vehicle. Without properly functioning spark plugs a vehicle may not start. If the vehicle does start the emissions can be heavily polluted. The process of replacing spark plugs is long, so most people opt to have them changed by a professional at an automotive shop.

10. Faulty Oxygen Sensor

The oxygen sensor regulates the fuel to air ratio and the emission control system, and helps the car maintain the correct levels. If the oxygen sensor is broken then your vehicle will not self-regulate, and will release harmful pollutants into the air.

For many cars there are multiple oxygen sensors present. So, if the oxygen sensor is not regulating it can be difficult to determine what the underlying problem is. This problem can be addressed by a local mechanic or autobody shop.

11. Disconnected Battery

A disconnected battery results in a vehicle that will not run. Reconnecting the battery may be something you can do at home, or you can call a local mechanic.

If the battery has been recently disconnected and reconnected your vehicle might fail an inspection. It will take a vehicle time to register all of the components after the battery has been disconnected. Driving the vehicle 50+ miles on average after reconnecting the battery may be necessary to pass an inspection.

12. Window Tinting

Every state has its own rules on window tint. A vehicle that does not meet the states requirements for window tinting will fail an inspection. To remove window tint yourself use soapy water and gently remove the tint with a razor blade.

13. Computer Reset

If your vehicles computer has been recently reset your vehicle may not pass its inspection. The computer takes time to sync with the rest of the car, so the inspector may not be able to determine if all aspects of the vehicle are working.

14. Broken Glass or Mirrors

If a cars glass or mirrors are broken the vehicle will fail an inspection, even if it is just a small crack. This includes front and back windshields, each car window, headlight plates, interior and exterior mirrors.

Even a crack that does not obscure the driver’s line of sight will cause a vehicle to fail an inspection. To fix a vehicle’s broken glass or mirrors visit your local automotive shop.

15. Windshield Wiper Malfunction

Another element of your vehicle covered during an inspection is whether or not the windshield wipers are functioning promptly. This includes the wipers themselves and the windshield fluid. Replacement wipers cost on average $70 for a pair, and can be installed at home or by a local mechanic for a small charge.

16. Broken Speedometer

The speedometer measures the speed of the vehicle. If the speedometer is broken the driver cannot determine what speed they are moving, which can be dangerous. A broken speedometer costs $150-$250 to replace.

17. Weather Conditions

Another contributing factor that can cause a failed inspection for your vehicle is wet weather conditions. Wet weather creates more work for the engine, which will increase the environmental pollutants in the air.

When the vehicle has to work to achieve its ideal internal temperature things are more likely to go wrong. Scheduling an inspection during ideal weather can impact the results of an inspection.

A car inspection will cover a long list of vehicle attributes. To avoid failing your inspection, take some time to check these common issues that cause vehicles to fail.

What Do the Vehicle’s Dash Lights Indicate?

The lights on a vehicles dash are there to warn the driver of potential issues their car is having. Understanding what these symbols are can help a driver determine when it is safe to operate their car, as well as attend to the needs of their vehicle. Below you will find the most popular dash lights and what they indicate.

Battery charge: This light appears as a rectangle with a plus and minus sign on each side, and indicates low battery. When this light comes on it could mean the car needs a new battery, or that the battery connection is poor.

Brake warning: When the handbrake is on this light will pop up on the cars dash. This light will appear as an exclamation point wrapped in a circle.

Engine temperature: The engine temperature light appears as a thermometer surrounded by two squiggly lines. This warning indicates the engine temperature has exceeded its normal degree. The driver should check the fan operation, coolant levels, and radiator cap when this light comes on.

Oil pressure: The oil pressure light appears as an oil can on the dash when the vehicle is experiencing a lack of lubrication. When this light comes on the driver should check their oil level immediately.

Safety symbols: In addition to warning lights, the cars dash may have a safety light come on. These lights are to warn the driver of unsafe driving conditions, such as a passenger is not wearing a seatbelt, or the roads are icy.

What is the Difference Between a Personal and Commercial Vehicle Inspection?

Different states have varying rules for inspection for commercial and personal vehicles. Understanding what your vehicle classifies as, and the general guidelines for inspection is an important step to staying safe and avoiding fines.

Inspection frequency: A commercial vehicle is required to undergo inspection every 12-months by a qualified automobile inspector. Depending on the state you reside in you may be required to undergo a privately owned vehicle inspection. The frequency varies by state. Only 15 states leave inspections to the discretion of the vehicle’s owner.

Inspection process: Commercial vehicles must undergo three different types of inspection including safety, emissions testing, and VIN. Personal vehicle inspections can incorporate all three aspects, or just one type of inspection.

Type of vehicle: Vehicle’s that would be considered for commercial use include buses, trucks used for work purposes, taxis, travel trailers, certain vans, and heavy equipment. Each of these must follow the regulations of commercial inspection, while private cars fall under the personal vehicle laws for inspection.

Vehicle inspection location: Where and how to have your vehicle inspected varies between personal and commercial. Personal vehicles can be done by a private inspector or at your local mechanic. For commercial vehicle’s check with your local mechanic and see if they are a certified vehicle inspector. If not, most automotive shop chains have the qualifications you’ll need to have your vehicle inspected.

How Much Do Vehicle Inspection Cost?

Many automotive service facilities offer vehicle inspections at a reasonable cost. The standard inspection for a personal vehicle costs between $60-$150, while a commercial vehicle may be more expensive ranging from $100-$200. As a vehicle owner you may wish to call and receive a couple different quotes on your inspection. Some service facilitates offer regular customer discounts.

What is An Emissions Test and Why Would A Vehicle Fail?

An emissions test measures the pollutants a vehicle is releasing into the atmosphere. An irregular air to fuel ratio is the most common cause for a vehicle failing an emissions test. Other reasons your vehicle fails its emissions test include, a loose gas gap, faulty spark plugs, the “check engine” light is turned on, a dirty air filter, or the car is overdue for an oil change.

What is a Tail Pipe Test?

A tail pipe test involves sticking a probe into the cars tailpipe to check the emissions. This test will measure the emissions, but does not help to determine what underlying issues are causing emission inconsistency. The probe can also be placed in the gas cap. The tail pipe test is a very limited method for emissions testing, because there are only two placed the probe can go.

Why is a Visual Catalyst Inspection Conducted?

Cars manufactured in 1975 or more recently must undergo a visual catalyst inspection. This inspection looks at the condition of the catalyst to ensure it is not missing, and has not been tampered with. If your vehicle weights more than 8501 pounds, is gas operated, and falls within the manufactured year range, then a visual catalyst inspection is necessary.

Wrap up

Having your car inspected is part of car ownership. Whether you use your vehicle for personal or commercial use an inspection ensures it is safe to drive. Understanding why your car might fail an inspection can help avoid repeat inspections. Knowing the tests that may be performed during an inspection will help you understand the results of your vehicles inspection. If you are interested in how to pass a car inspection please leave a comment below.

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