A Complete History of the “Check Engine” or “Service Engine Soon” Light

Have you ever wondered where the check engine light in your car came from? How did it come to exist as we know it today? It’s actually come quite a long way from its earliest stages, which dates back to the 1930s. Interested? Stick around to find out more.

How do check engine lights work these days?

Before we go back in time, let’s review how check engine lights work today. A check engine light is a computerized warning that indicates an engine malfunction. Usually found on the dashboard, it’s the red or orange light that tells you there’s an issue with your vehicle. It either looks like an image of an engine, or will sometimes show up as a phrase, such as “SERVICE ENGINE SOON”. When the check engine light is activated, the engine control unit saves a diagnostic trouble code (DTC). This code gets read by an auto technician using a scan tool.

Where did the idea of a check engine light come from?

The earliest form of the check engine light was known as an idiot light (no joke), or warning light. These were first used in vehicles manufactured in the 1930s by the Hudson Motor Car Company. Idiot lights only switched on when a major issue or breakdown was about to occur. The problem with these binary lights was that they gave no advance warning of a vehicle fault. Although they were a popular auto feature for several decades, they were eventually discontinued in the 1980s.

Manufacturer-specific check engine lights

Idiot lights were discontinued to avoid confusion with a new form of the check engine light. In the early 1980s, auto manufacturers built new vehicles with computerized engine controls. With this new technology came a basic diagnostic system that monitored automobile issues. Each vehicle’s diagnostic system was unique to its manufacturer. They activated the vehicle’s check engine light when an issue arose. However, since there was no organized use of DTCs, it was very difficult for a technician to get to the root of the problem. Since each automaker had its own diagnostics system, identifying the reason for a check engine light was a lot more complicated than it is today.

When was the check engine light standardized?

Starting in 1996, an on-board vehicle diagnostics system, known as OBD2, became a requirement for all vehicles sold in the United States. The reason for this was a federal mandate designed to lower vehicle emissions. Since all new cars had to have OBD2 technology, a standardized system of DTCs was established. Because of this system, our skilled technicians at Bonfe’s Auto in St. Paul can use scan tool technology to diagnose issues in any vehicle.

As you can see, we’ve come a long way since the early days of idiot lights. Today, auto technicians can diagnose any issue on any vehicle in no time flat. Since check engine lights are activated for a variety of reasons both large and small, they detect issues before they become a big problem. This can save time and money on repairs.

That wraps up our history lesson on the check engine light. The next time you see that your car’s check engine light is activated, just be grateful it’s not an idiot light. Think of it as your car’s way of telling you it needs some extra care, pick up the phone, and give us a call.


8 Reasons Your Car’s Check Engine Light is On and What You Need to Do About It

No one wants to see their check engine light turn on. Car problems are stressful, but having some understanding of what can go wrong helps you stay prepared. Below are 8 reasons why your vehicle’s check engine light (CEL) is on, and what you can do about it.

1. Spark plugs and spark plug wires

A malfunction with your spark plugs and spark plug wires can activate the CEL. Spark plugs ignite the fuel and air in your engine to produce power. If these parts are faulty, it could affect performance or even cause your engine to stop running altogether. Luckily, spark plugs are relatively inexpensive and easy to replace.

2. Catalytic converter

If your CEL is triggered by a problem with your catalytic converter, then you have a more serious problem on your hands. Since it doesn’t need routine maintenance, a faulty catalytic converter is usually due to an underlying issue with spark plugs or oxygen sensors. If these repairs are neglected, it can lead to bigger problems down the road.

3. EGR valve

The EGR (exhaust gas recirculation) valve controls gas flow as it travels from the exhaust manifold to the intake manifold. Your car’s CEL may turn on if the valve detects a gas flow that’s higher or lower than the average amount. This happens when the valves get clogged up by carbon build-up, causing them to stick. EGR valves don’t need routine maintenance, so a clogged valve generally happens when there’s another problem with your engine.

4. Vacuum leak

A vacuum leak is another reason you may be seeing your CEL. This happens when the vacuum’s rubber linings stretch out or crack. The vacuum is connected to a lot of other systems in your car, including the exhaust, brake booster, heating and A/C vents, and cruise control. If you have a vacuum leak, you probably also have issues with one of these components.

5. Loose or missing fuel cap

Your gas cap prevents vapors from escaping the gas tank. If your gas cap is faulty or missing, your car will let you know by illuminating the CEL. Driving with a missing or faulty gas cap can seriously reduce fuel efficiency and increase emissions. Luckily, this is an easy, low-cost fix.

6. Oxygen sensor

Your car’s oxygen sensor tells how much oxygen is present in the exhaust. This lets your car know how much fuel it needs to operate. If the sensor isn’t working, your car will think it needs more fuel than necessary, and the CEL will be triggered. Delayed maintenance can cause bad gas mileage. There’s also potential for damage to other engine parts, which could lead to thousands of dollars in repairs.

7. Battery

A faulty battery will definitely activate the CEL. The battery is essential to starting and operating your vehicle, so it’s important to address this immediately. Our technicians at Bonfe’s Auto always test car batteries during vehicle inspections.

8. MAF failure

A mass air flow (MAF) sensor failure is another reason your CEL may be on. This sensor measures the amount of air entering the engine. If it’s not working, your car won’t know how much fuel it needs. A faulty MAF sensor could cause problems with your catalytic converter, spark plugs, or oxygen sensor.

As you can see, your check engine light alerts you to a wide array of vehicle issues, and they’re not always easy to diagnose. That’s where we come in. Our technicians at Bonfe’s Auto are ready to help. Give us a call at (​651) 222-4458 to book your appointment today. We look forward to providing you with quality service.



What to Do When You See Your Check Engine Light

You hate to see it. The dreaded check engine light. As you know, it can indicate a lot of different issues, both large and small. Either way, don’t ignore it, or you could wind up with bigger problems down the road. Let’s talk about what steps to take to troubleshoot your car’s check engine light.

Should I pull over?

Chances are, you’ll be driving when you notice the check engine light. The first decision you need to make is whether or not to pull over. Here’s what you need to know. When you see the check engine light, it’ll either show up as illuminated or blinking. If it’s blinking, it indicates a major vehicle malfunction. If that’s the case, you definitely need to pull over right away. If the light is illuminated by not blinking, it usually means a less serious engine problem. It still needs to be handled as soon as possible, but chances are you don’t need to pull over to the side of the road.

Either way, blinking or not, you should always assess the situation. Look for any indications of a serious problem. For instance, if you see or smell engine smoke, experience loss of power, or hear odd noises, it’s probably something major. In this case, pull over and avoid driving if possible. Your best bet is to get your vehicle towed to a service provider for an inspection.

Troubleshooting the check engine light

If you don’t have a serious engine malfunction, there’s a few steps you can take to address the illuminated check engine light. One place to check is your oil dipstick. Take a look at it and make sure it’s seated properly. Make sure the oil fill cap, which is found on top of the engine valve cover, is tightly secured. Taking these steps may turn off your car’s check engine light. Another spot to check if your fuel cap. Believe it or not, a loose fuel cap can trigger your car’s check engine light. Look for any damage or cracks, and make sure it’s tightened all the way. This may deactivate your check engine light.

To get a better understanding of why your check engine light is on, you can invest in an OBD2 scanner. When connected, this gadget reads the diagnostic trouble code (DTC) associated with your check engine light. Hook up the OBD2 scan tool to the data link connector, which is located beneath the dashboard on the driver’s side.

A good OBD2 scanner costs somewhere around $50 to $100. This tool will point you in the direction, but it doesn’t give you a ton of specific information about what’s going on. It does give you a sense of how severe your problem is. This can help you decide how to move forward with repairs. Try not to panic when you see the check engine light. Take a deep breath and take stock of the situation. Develop a plan to solve the problem. Remember, if you have an urgent matter, pull over and seek help right away.

Here at Bonfe’s, our experienced technicians can handle anything that comes our way. We’ll do our best to get you back on the road in no time flat. Give us a call at (​651) 222-4458 to schedule your appointment today.


Headlight restoration is an act of refinishing the old headlights that have turned out to be discolored over time due to oxidation from the UV light and other environmental factors. When we talk about driving at night, as a driver, one of the most important safety measures you can take is if the headlights are in optimal working.


Most headlights these days are manufactured using a polycarbonate plastic, which makes headlights more durable and prone to dents. However, there are certain signs that you can’t overlook. The signs that add up and make the restoration of headlights an important task is listed as follows…

  • Foggy headlights are an easy way of telling you to need headlight restoration.
  • While two of three scratches won’t make a difference, but a load of them most certainly will. Scuffed or scratched lenses are another sign for you to add the headlight restoration on your to-do list.
  • One of the main reasons is poor nighttime visibility.

On average, it takes 10-20 minutes on every headlight. Larger headlights are harder to stand will require more time.


Notice loaded dents or scratches on the headlight, and it will be obvious why you need to get it checked. Also, if you see the light emanating from the headlights is less than usual or used to be, the chances are high that your vehicle is suffering from the fog. Sometimes drivers notice that their headlights are not as bright and have a dingy tinge to it, which is also caused by headlight fogging.


If your headlights are slightly foggy and you think you can restore them at home, then take an abrasive toothpaste and some scrubs. Clean the headlights using soap and water. Use a soft cloth, and with a fingertip amount of toothpaste rub it on the wet headlight; for better results, try baking soda with water.

Sometimes the headlights are extremely damaged or fogged. Make sure to contact us and ask for professional assistance. This will help provide you with the best visibility possible when you drive.


Now that you know the importance of getting the headlight restoration hire a professional to check your headlights for you! Bonfes Auto provides you with both experience and expertise to help you keep your item clean. And you can acquire these services right here in St Paul, MN.


When is the Best Time to Buy Tires?

Sometimes it can be a bit difficult to tell if your car needs a near set of wheels. While some experts say that Fall is the best time of the year to buy new tires, although there is no hard data to support such a black-and-white conclusion.

When To Change The Tires For Your Car?

In reality, the best time to buy tires is before you need them – while this may sound a bit too ambiguous, you need to have an extra pair of wheels before you get stuck in an emergency. For instance, if you are caught on the roadside with a flat tire, you might be willing to pay any price to get back on the road again.

With that out of the way, let’s discuss what the best time to buy tires is. Buying tires can be costly, especially if you are planning to buy all four at once. According to several car enthusiasts and experts, the best time to buy tires is around October, just before winter, and again in April when the weather gets warm enough and people are planning road trips and joy rides. It is also in these months when tires go on sale, allowing buyers to save a significant amount of money.

Tires need to be replaced before the tread gets below 2/32 inch – if you do it sooner, it will maintain proper handling and braking before your current set is worn out. It is recommended that you don’t wait for the tires to wear off, rather play it safe and get them changed on time.

What Offers Are There For Buying Tires?

At Bonfe’s Auto, we are a trusted and reliable auto service and body repair shop in the heart of St Paul, Minnesota.  To learn about what tire specials we have available give us a call at: 651-224-7572  or stop by.

Bottom Line

Getting your tires replaced at the right time is very important. It protects you and your loved ones from facing roadside emergencies, giving them a smooth driving experience. Bonfe’s at St Paul, MN, can inspect your vehicle to ensure it is operating the best it can.

Brake Repair: How to find a good auto service center

Finding the best auto service center ought to be an essential worry for any individual who drives all the time. Getting found napping by an unforeseen breakdown can leave you with no solid spot to turn for help. In any case, there are a few different ways you can keep an awful circumstance from deteriorating by setting aside the effort to locate a reliable auto service center now rather than later.

How to maintain the brakes

Have your brake and brake cushions checked once every year. If they are too worn to even think about working appropriately, have them supplanted. Check your brake liquid consistently. Your vehicle’s brake liquid is fundamental to move the heat to all pieces of the slowing mechanism and assimilate water. If the liquid is a dim shading, it might be an ideal opportunity to have it flushed. Tune in and watch for notice signs. These may incorporate strange noises, unusual brake reaction, and anomalous inclination when you push on the brakes, and they may show a hazardous issue that you ought to have looked at immediately.

Signs of brake wear

At the point when one of the red or yellow brake markers on your dashboard illuminates, it might mean you’re only due for an investigation. It could likewise be your vehicle’s shrewd hardware making you aware of an issue if you begin hearing a piercing clamor that stops when you apply the brakes that are likely the sound of the brake cushion wear markers. They’re made of steel, so they make this sound when they begin reaching the rotor.

What makes up the brake system

Most present-day vehicles have brakes on every one of the four wheels, worked by a pressure-driven framework. The brakes might be plate type or drum type. The front brakes have a more prominent influence in halting the vehicle than the back ones because it is slowing down tosses the vehicle weight forward on to the front wheels. Numerous vehicles accordingly have drum brakes, which are commonly more productive, at the front and drum brakes at the back. All-drum slowing mechanisms are utilized on some costly or superior vehicles and all-drum frameworks on some more established or littler vehicles.

One last factor that makes an extraordinary auto service center stand apart is their ability to guarantee their work. Be explicit when you ask about the guarantee for your vehicle and see whether it covers only the brake parts or the work also. An auto service shop that guarantees parts and work remains behind their work and needs to procure your trust.

So, are you having brake problems in your car? Then, connect with Bonfes Auto. Providing you with the service of best brake repairs right here in St. Paul, MN. Keep your car brakes functioning at its maximum! Contact us now!


Driving a car is all excitement and fun until you have to get under the hood. There is so much going on that just a single glance can stress you out. While there are professionals out there to help you, there are a few things that you need to educate yourself about, at least about the super important components, such as a cabin air filter.

So, what does a cabin air filter do, and why is it so important? It is that component of your car that works to keep the contaminants and harmful irritants at bay. From microscopic dust particles to pollens, these filters remove all pollutants from the air that you are exposed to in the car. If you or your loved ones suffer from allergies or asthma, you need to make sure that this component of your car functions perfectly.

The Significance

The cabin air filter is part of a vehicle’s HVAC system that is responsible for filtering the air that enters the driver’s and passenger’s compartment. The quality of air that you breathe can affect your respiratory system and worsen the situation of already existing respiratory problems. It traps the pollutant, allergens, and all other external particles that may lower the quality of air inside a car.

If you think that the presence of an air filter for your car cabin is not that important and you can do without it, you need to rethink it. Things can get really bad if you plan to drive without one, especially if you have a sensitive respiratory system.

Who would want to turn the driving fun into a life-threatening experience, right?

The Location

Cabin air filters are an integral part of a car, and they ensure that passengers are exposed to clean air in the car. These filters are pleated units that are small and very difficult to locate. Commonly manufactured using engineered materials, they are usually located behind the glove box. In other cars, it is sometimes placed beneath the dashboard or under the hood.

The Need to Replace

Like all other auto parts, even this filter will need to be replaced at some point. Not getting it replaced will give rise to a myriad of problems for you. With time, dust and debris accumulate on this filter, and a time comes when this clogs the filter, after which it fails to function at its full potential.

When this happens, expect a drop in the performance of your car’s HVAC system, which, as a result, will reduce the air volume in the passenger compartment. Not to forget the issue of foul odors in your space that arises due to a dirty filter. Now, imagine a car with foul odors and a malfunctioning HVAC system; it is definitely not a pleasant place to be in!

It is due to this reason that experts recommend drivers to replace the cabin air filters every 12,000 miles. If you have to regularly drive in a heavily polluted area in St. Paul, you might have to schedule a filter change every 5,000 miles.

The Perfect Timing

The question is not whether to replace a cabin air filter or not; it is when to replace it. It is a question that many people struggle with. To know the right time of replacement, you need to look at the signs that indicate that a filter has stopped working. The signs that we are talking about include;

Reduction in Air Flow

When a cabin air filter begins to get clogged, you will experience a reduction in the airflow in the passenger’s compartment. A dirty filter fails to allow contaminant-free air to flow through it, which weakens the airflow. The AC blower motor might also get affected.

Funny & Odd Smells

Many drivers and passengers begin to feel funny and odd smells seeping into a car’s cabin from the vents. These odors and smells point directly towards a clogged or a dirty cabin air filter.

Decreased Fuel Mileage

Have your trips to the gas station become more frequent than usual, and are you experiencing a drop in your car’s fuel mileage? It is time that you get your car’s cabin air filter replaced. The overall fuel economy drops after these filters stop working.

Cabin air filters are critical for your health as they maintain the quality of air inside the car. With this guide, you can immediately get these filters changed if you are experiencing ‘the signs.’ You can even locate the filters and take the matters in your hand, but some things are better left for the professionals to handle. Instead of taking matters in your hand, you can take it to a professional auto repair service in St. Paul, MN.