Did you know that the check engine light in vehicles dates back to the 1980s? However, it had a predecessor, referred to back then as “idiot light.” As vehicles became more complex, the check engine light replaced the idiot light.
Since then, the check engine light became the standard malfunction indicator lamp (MIL).
As a defect indicator, it’s understandable that you’d worry if your check engine light comes on. After all, car ownership now costs over $9,000 per 15,000 miles. If your vehicle’s MIL lights up, it can mean a considerable increase in your costs.
To that end, we created this guide on what to do if you find yourself looking at an illuminated check engine light. Read on to discover the steps to take, as well as which car problems you can fix on your own and when you need a mechanic.
Reduce Your Speed
As LeMans Milton Mechanic points out, there are at least 30 popular car makers worldwide. Some of these manufacturers equip their cars with a text-based MIL that says “Check Engine.” Others use only an image of an engine or just the word “Check.”
The color of the light also depends on the manufacturer; some use yellow, while others use amber or red. Some carmakers also distinguish engine problem severity by the light’s color. Yellow or amber signals an important but less serious issue, while red is a sign of an emergency.
With that said, a lit check engine light doesn’t always mean you need major car repairs. However, it does mean something’s wrong. It came on because your car’s onboard diagnostic (OBD) system detected an engine issue.
You’d want to slow down, especially if the MIL light came on and you noticed a sudden drop in your ride’s performance. This may indicate that your engine is having trouble meeting your demands.
Another reason to slow down is to check if other warning lights on your dashboard came on. An illuminated engine temperature warning light indicates an overheating engine. If the oil pressure light came on, it could mean you’re low on oil or your oil pump isn’t circulating fluid properly.
If other warning lights came on with your check engine light, pull over as soon as it’s safe to do so. This is even more important if the check engine light flashes on and off. A blinking MIL often indicates a severe engine problem, such as a misfire.
Pop the Hood
Maneuver your car to a safe spot where you can park it and check what’s under your hood. In many cases, a steadily lit check engine light indicates a loose gas cap. Tightening the cap is a simple task you can do on your own.
You should also check your fluid levels, as running low on them can trigger your vehicle’s MIL to come on. Let your engine cool for about 20 minutes before you check each of your fluid tanks.
If there’s any tank running low, take your ride to the nearest station, where you can top up your fluids. A refill should deactivate your check engine light.
Bring Your Car to a Mechanic Right Away
If your MIL blinks non-stop and has excessive vibrations, the engine may be misfiring. The same goes for if your car accelerates roughly, is slow to speed up, or its engine makes loud noises. All these are signs of a misfiring engine that warrants immediate professional inspection.
Do the same if your check engine light turns red from yellow or orange. A red MIL that comes with the symptoms above also indicates a misfiring engine.
Such events require prompt inspections as engine misfires can damage catalytic converters. A misfiring engine can also result in a vehicle producing excessive exhaust fumes.
If you notice any of those signs, your next stop should be a car repair shop. Otherwise, your catalytic converter or engine can sustain more severe damages. Worse, road enforcers can stop you and slap you with a hefty fine for exhaust pollution.
Check For Leaking Fluids
If your check engine light comes on again after topping up your fluids, you may have fluid leaks. You can continue driving home, so long as it’s nearby. You can then do fluid leak tests as soon as you get home.
To perform the test, place a few clean towels on level ground. Park your car in a way that the engine sits right above the fabrics. Wait for a few hours, or if it’s late, check the towels for any stains the following day.
Red oily marks that smell like petroleum are signs of transmission fluid leaks. Reddish-brown spots reminiscent of toasted marshmallows indicate power steering fluid leaks. Brown stains signal engine oil, brake fluid, or dirty transmission fluid leaks.
As for coolants, they come in many colors, including blue, green, pink, purple, or red. However, they usually carry a sweet scent, which makes them easier to distinguish.
Whatever the color of the stains, visiting a mechanic should be your next order of business as soon as you see them. An experienced mechanic will nail down the exact type of fluid your ride is leaking out. From there, the expert can carry out the repairs or replacements on the damaged fluid lines or tanks.
Change Old or Contaminated Fluids
Speaking of fluids, your check engine light may also come on due to dirty oil. Fluid contamination can also trigger your vehicle’s MIL to light up. So, aside from checking for fluid leaks, be sure to pay attention to the color of your fluids, too.
Clean engine oil is light brown, so if yours has turned dark brown or even black, you need an oil change. If your transmission fluid is now milky-pink, that’s a sign of contamination, so you need to flush it.
It’s imperative to drain dirty or contaminated fluids before you replace them. Even a tiny bit of leftover fluid can already make the fresh supply go bad, too. If you have tainted fluid, you need to flush it before changing it.
A fluid change involves draining the old or dirty fluid before replacing it with a new supply. A fluid flush comes with the extra step of cleaning the fluid container.
For example, to flush a contaminated coolant, you need to drain it first and then clean the radiator. The latter involves filling the radiator with clean water and then running the engine for a bit. After this, you need to drain the water before you top up the tank with fresh coolant.
Simply changing dirty fluids can take about an hour, but a flush takes twice or thrice longer. You also need to follow mandatory protocols on handling used automotive fluids. According to the EPA, four million people either recycle or reuse their motor oil.
If you plan to recycle used motor oil, be sure to store it in a seal-tight container. You can then take it to a recycling facility. Or, you can let a pro mechanic handle everything on your behalf.
Replace Your Spark Plugs
Spark plugs supply the spark needed by an engine to ignite the air and fuel in its cylinders. This spark is what allows your engine to create an explosion that then pushes your car forward. Without spark plugs, vehicles won’t be able to move at all.
With their role, spark plugs must be durable to withstand all those micro-explosions. However, they would still require replacement after thousands of miles. Some makers recommend changing them after 30,000 miles, while it’s 100,000 miles for others.
Your check engine light could come on if your spark plugs are nearing the end of their useful life. Aside from the light, you’ll also experience difficulties getting your engine to fire.
However, early spark plug failure occurs, too, and is usually due to bad installation. Chemical contaminants can also cause early spark plug corrosion. Either way, a failed spark plug will make your check engine light come on.
Changing spark plugs on your own can take about an hour or so for a four-cylinder engine. You need access to the right set of torque wrenches and spark plug sockets, though. If you don’t have the proper tools, bring your ride to a mechanic, as you can risk damaging other parts of your engine.
Follow These Steps as Soon as Your Check Engine Light Comes On
There you have it, your ultimate guide on what to do if your check engine light comes on. Reducing speed should be your priority if it lights up as you’re driving. However, if your engine is misfiring, make sure to bring your ride to the nearest mechanic right away.
Ready for more automotive guides that can help keep your ride in tip-top condition? Feel free to browse our site’s other categories to find more tips and tricks like this!