Car Repair and Maintenance

What to Do When Check Engine Light Comes On

The check engine light? “Damn, this annoying light!” You’d exclaim. But you can fix it. This article reveals what to do when the check engine light comes on, and I have mentioned the common causes of the problem. Yes, we all detest this one light lighting in the dashboard.

what to do when check engine light comes on

Well, what you can do when the check engine comes on depends on your car. The first remedy step, however, is to refer to the owner’s manual.

Meanwhile, the check engine light typically occurs when degradation has been detected in the combustion process. Your onboard computer may be signaling inefficient fuel-consumption compared to the manufacturer’s specification. A common instance in older vehicles is a failed oxygen sensor. In this case, your car attempts to modify the air/fuel mixture to operate efficiently by snuffing for oxygen in the exhaust.

A check engine light on your car does not mean towing it for repairs immediately, except it drives with visible liquids or gas and strange sounds, typically knocking.

In essence, the check engine light may signify poor fuel economy, reduced performance, and increased emissions. Meanwhile, you can’t pass the smog check with increased emissions.

What to Do When Check Engine Light Comes On

So, how do you deal with the check engine light? Let it be? Fight it immediately? Well, this section discloses the steps to get rid of the engine light.

Below is what to do when the check engine light comes on:

  1. Check Onboard Diagnostic System

Your vehicle features an onboard diagnostic system that notifies when issues arise in the engine. If the problem is critical, the check engine light flashes/shakes instead of lighting steadily, enabled by your diagnostic system.

You must not drive your car in this condition until you have a professional technician sort and fix the problem.

But if the check engine light is still on, you can drive the car without an emergency check-up. You can also review the problem before contacting a professional technician.

  1. Disconnect the Battery

The first home remedy for check the engine light is to disconnect the battery. Make sure not to reconnect the battery until after at least 10 minutes.

You will need to turn on the ignition to confirm whether the light is off or still on. If the annoying check engine light is still on after replacing the battery, consider the following steps.

  1. Tighten Your Gas Cap

A loose gas cap can bring on the check engine light. Of course, tightening the gas of your vehicle can fix the warning light.

Note, however, that you must cover several trips for the check engine light to reset. If your car features a separate loose gas cap indicator, refer to it before setting the cap well.

  1. Check Belt, Plug, and Wire

Belt, plug, and wire are possible culprits behind the check engine light. But if accessory belts and fans are okay, inspect further for adrift wire plugs. You can also check whether all wires are terminated or corroded.

  1. Watch Your Engine Load and Speed

Is the check engine light flashing? Do you notice severe performance problems like reduced speed and power loss? If “yes,” offload/reduce the engine load and slow your speed.

Regarding the engine load, if you have a small car that tows 3000+ lbs, for instance, stop towing temporarily. Monitor the vehicle thereafter, and when you notice no changes, have the vehicle checked to avoid costly replacements.

  1. Report the Codes to a Mechanic

A typical check engine light results from DTC (Diagnostic Trouble Code). If you can’t read the codes, consult a local auto shop to read the trouble code.

Trained mechanics typically use sophisticated and specialty tools to troubleshoot the code responsible for the check engine light. Nonetheless, reading and sorting codes do not entirely imply fixing the warning light; an auto technician must diagnose the vehicle to fix the problem.

Somehow, getting a single code signifies a failed sensor. Real problems, however, generate 3-4 codes. The reason is that the internal combustion engine is interrelated, meaning that one problem leads to many complications.

Note that many auto part stores read codes for free. When you get the codes, use a search engine such as Google, DuckDuckGo, or Bing to look it up.

  1. Do Not Go for Emission Test

A car with a check engine light on will most likely fail the state’s emission test. Some states award instant failure, even on the loose gas cap and other minor irregularities.

So, before you go for a smog check or emission test, make sure to get rid of the check engine light warning.

Flashing Vs. Still Check Engine Light

Understand that both flashing and solid or still check engine indicate a problem in your car. But when the check engine light is flashing, it signifies a severe or critical vehicle problem that must be sorted urgently. Consult an auto technician immediately; otherwise, you would be incurring hefty expense on replacements.

Meanwhile, depending on your car, the check engine light color may display in red or orange. If it displays red/orange instead of yellow and without shaking, it indicates a critical problem.

In essence, make sure to have your car diagnosed and fixed whether the check engine indicator light is still/solid or flashing.

Although a flashing check engine light signifies critical engine problems, ignoring the still warning light can result in costly repairs eventually.

But what if the check engine light is shaking/flashing?

Like I mentioned earlier, have your car checked ASAP. When the check engine light flashes and you continue driving your car, it exposes the car to expensive damage.

Most of the time, it damages the catalytic converter, which is expensive to replace. Do not follow the recommendations regarding how you can deal with your car’s check engine light outlined in this article if yours is flashing or displaying still as red. Get the vehicle to a mechanic to diagnose and repair it.

Why Check Engine Light Comes On

What is the most common reason for check engine light

I assume you may be interested in the misery behind check engine light coming on. Below are the reasons why check engine light comes on:

  • Engine

Yes, problems within the engine apartment trigger the check engine light to turn on. So, your vehicle can detect these problems using a control module that tracks and monitors engine operations with sensors.

  • Ignition

Your ignition system comprises coil packs, spark plugs, and other components important for igniting air/fuel mixture in the vehicle engine.

  • Transmission

Tailpipe emissions increases when there is a problem with the transmission, which causes the check engine light to come on. Thus, the control module discovers the transmission problems and alerts/warns you to administer a fix.

  • Emission System

Most modern cars sufficient onboard emission equipment. You have the catalytic converter, exhaust gas recirculation system, evaporative emissions system, etc.

Now, each of these systems is built to mitigate and optimize tailpipe emissions; thus, ensuring less environmental emission pollution and ventilating the atmosphere.

  • Air and Fuel Delivery

If your vehicle does not have sufficient air and fuel, it can’t run properly; thus, the check engine light comes on.

Is it safe to drive your car with the check engine light on?

Yes, it is safe to drive your car when the check engine light is on, but if the light is flashing or red, it is not safe to continue driving. It is fazing when a check engine light comes on while the car is moving. However, if the light is still and the vehicle performance is OK without strange noises and leakages, you can administer a home remedy or consult a mechanic.

Where do I go when my check engine light is on?

Where do you go when your check engine light is on? The mechanic, of course. You will pay a fee for diagnostic or have the auto parts shop read the code at no cost. When you get the code, search online for the meaning. Do not rely on self-diagnosis, especially when the check engine light is flashing or displaying red, which may be critical.

Can low oil cause the check engine light to come on?

Yes, lower oil pressure can cause the check engine light to turn on. The light shows interference with your vehicle performance and your oil light will display. Typically, extremely low oil can disable your car.

How many miles do you have to drive to clear a check engine light?

You may have to drive between 30 and 100 miles to clear a check engine light. During this period, various sensors recalibrate, and the drive cycle of your car resets.

How much does it cost to get your check engine light checked?

An auto mechanic will charge a $100 fee to diagnose a check engine light. Most auto part stores, however, will not charge a fee to read the codes, which may present minor issues you can fix.

Final Thoughts

At this point, I believe you know exactly what to do when your check engine light turns on. If after following the remedies mentioned in this article, the light remains, consult a mechanic and have your vehicle scanned.

Do not make the mistake of replacing parts you believe are common causes because of the “common faulty parts” notion. When you ignore or delay professional diagnosis, you might spend more money to replace faulty parts.

Bernard Juchli
Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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