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.