History of the "Check Engine" or "Service Engine Soon" Light

How often have you stopped to think about your car’s check engine light? Probably not a ton. You might be surprised to hear that its history dates all the way back to the 1930s. Interested? Stick around to learn all about the evolution of this handy invention.

How do check engine lights work these days?

Let’s go over a few basics before we get into the details. A check engine light is sometimes called a malfunction indicator lamp, or MIL. It’s the red or orange light on your dashboard that appears when there’s an engine malfunction. It’s operated by your car’s computer, or diagnostic system. When the diagnostic system detects an engine fault, the check engine light is triggered. A fault code is simultaneously saved. This code, called a DTC (diagnostic trouble code), is what our technicians at Lloyd’s Automotive use when performing vehicle diagnostics.

Where did the idea of the light come from?

The earliest form of the check engine light came from the Hudson Motor Car Company of Detroit, Michigan. In the 1930s, they began installing idiot lights (real name) into their vehicles. Idiot lights were warning lights that served as tell-tales for serious engine malfunction. These lights were binary, so they only switched on when there was a big problem with the car. That means they didn’t give much advance warning before your car broke down. Idiot lights weren’t very helpful, but they remained a popular feature until the 1980s. At that point, they were phased out to avoid confusion with a new technology.

Manufacturer-specific check engine lights

In the early 1980s, automakers began selling vehicles with computerized engine controls. These cars had internal computers with entire diagnostics systems. This system was much more comprehensive than an idiot light because it could alert you of a wide range of issues. However, these manufacturer-specific systems weren’t flawless. The main issue was the lack of regulation. Each automaker used their own system, making the auto technician’s job quite difficult.

History of the Check Engine Light

In 1996, the U.S. government mandated the use of an on-board vehicle diagnostics system, called OBD2. OBD2 triggers a vehicle’s check engine light anytime fuel emissions exceed the federal limit by 1.5 times. Since all new cars had the same technology, it resulted in the standardization of DTCs. This allows auto technicians to read DTCs with a scan tool, which saves time when pinpointing an issue.


Thankfully, technology has come quite a long way since the 1930s. Scan tools let auto technicians assess any vehicle, regardless of the make or model. Since check engine lights get triggered for a number of reasons, they often alert you to non-urgent issues. This leads to preventative maintenance, which saves you both time and money in the long run.



There you have it. A brief history of the check engine light and how it’s changed over time. The next time you notice the check engine light in your vehicle, think about how far it’s come. Consider it your car’s way of talking to you, and give us a call.

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

Nothing ruins a great drive by looking down at your dashboard and seeing your check engine light. While it may be tempting to ignore, doing so will only cause you a bigger headache. The check engine light can indicate a problem with any number of things, and at Lloyd’s Automotive, we’re experts at figuring out exactly what’s going on. Let’s discuss 8 of the most common reasons you’re seeing the check engine light in your car.


1. Catalytic converter

Your engine’s catalytic converter transforms carbon monoxide into carbon dioxide. Although it doesn’t need routine maintenance, it can get clogged. This prevents it from functioning properly, which will activate the check engine light. If that’s the case, chances are there’s another problem in your engine that’s causing it to clog.


2. Battery

If your light is triggered by your vehicle’s battery, it means that it’s not charging correctly. These days, batteries are maintenance-free and they last around 5 to 7 years. If it’s malfunctioning, your car’s computer will pick up the low voltage and alert you that it may be time for a replacement.


3. Loose or missing fuel cap

The fuel cap keeps debris from entering the gas tank, and also seals it off so no fumes can leak out. Your check engine light will turn on if the fuel cap is cracked, missing, or loose. This is a really simple and inexpensive fix, as long as you don’t put it off. Without it, your vehicle’s emissions will increase and you’ll have poor fuel economy.


4. MAF failure

The MAF (mass air flow) sensor tells how much air is in the engine. This tells your car computer how much fuel is needed for it to run properly. If there’s a problem with it, your check engine light will turn on. If left unrepaired, a faulty MAF sensor could damage your spark plugs, catalytic converter, or oxygen sensor.


5. Spark plugs and spark plug wires

Spark plugs and wires light up the fuel and air in your engine’s combustion chamber. If these are faulty, it can cause your engine to stop running. As long as they’re replaced right away,

you’ll have a minor repair on your hands. If you put it off, you may wind up with a damaged catalytic converter or oxygen sensor.


6. Vacuum leak

There are lots of vacuum lines in car engines. These are made of rubber, so they develop cracks and stretch out over time. When this happens, your check engine light will activate. Vacuum lines are cheap and easy to replace, but finding the source of the leak can be time-consuming.


7. Oxygen sensor

The oxygen sensor detects the amounts of gases in the engine to ensure there’s enough oxygen. Your check engine light may be on because of a faulty sensor. Delaying this pair could ruin your catalytic converter or spark plugs, costing you thousands of dollars in damages.


8. EGR valve

Your check engine light can sometimes be triggered by the EGR (exhaust gas recirculation) valve. Although this part doesn’t need regular maintenance, it can get clogged by carbon build-up. The EGR valve is controlled by your car’s computer. It gets opened or closed to control vehicle emissions by sending a portion of the exhaust gases back to the intake manifold. A clogged valve won’t do its job and will need maintenance.


As you can see, the CEL can be turned on by any number of issues. One problem could be connected to another faulty engine component. The only way to get to the bottom of it is to get your vehicle inspected. That’s where we come in.

Give us a call at (651) 228-1316 to schedule your appointment today.




Steps to Take When Your Check Engine Light Turns On

No one wants to deal with a check engine light problem. The truth is, that warning light can alert you to a number of engine problems, from simple to complex. No matter what, don’t just ignore it. Read on to find out what you should do when you see the check engine light in your car.

Should I pull over?

This is the first thing most people think about when they see their check engine light. Here are the facts. Your check engine light will either show up as a blinking or solid light. If it’s solid, it’s indicating a non-emergency problem. You should be safe to continue driving, but you need to get your vehicle serviced as soon as possible. If the check engine light is blinking, it’s telling you there’s a major problem, possibly an engine misfire. If this is the case, pull over as soon as you can.

No matter how your check engine light looks, you should always pay attention to your vehicle’s performance. Do you notice anything strange? Some obvious signs of engine trouble are smoke, odd noises, or loss of power. If any of these things are happening, stop driving right away. If you continue driving with a major vehicle malfunction, you could cause irreversible damage to expensive parts. Get your car towed to the nearest service provider.

Can I fix the check engine light problem myself?

If you don’t have a major vehicle issue, there are a few easy fixes that may turn your check engine light off and send you on your way. The first spot to look at is your gas tank. Something as minor as a loose fuel cap can activate your check engine light. Make sure it’s tightly screwed on. You’ll also want to check for any cracks or damage, since this can trigger the check engine light as well.

Another place to examine is your oil dipstick. If it’s not seated properly, your check engine light can turn on. In addition, a loose oil filler cap can also trigger your check engine light. Make sure the filler cap, located above the engine valve cover, is fastened correctly.

Another troubleshooting option is an OBD2 scanner. This handy tool detects the DTC (diagnostic trouble code) associated with the check engine light. To get the DTC, connect the OBD2 scan tool to the data link connector in your car. It’s typically located underneath the driver’s side dashboard.

OBD2 scanners can cost up to $100. They give you a pretty good idea of how serious your engine problems are, but they don’t tell the full story. Knowing the severity of your issues can help you decide how you want to move forward with repairs.

The check engine light is no reason to panic. When you see it, try to stay calm. Pay attention to what’s going on with your car, and make a plan. Remember, if you think you have a major vehicle malfunction, the safest thing to do is pull over as soon as you can.

When your car needs care, Lloyd’s Automotive is here to help. We diagnose and repair engine issues fast, getting you back on the road in no time. Give us a call at (651) 228-1316 to schedule your appointment today. We look forward to serving you.