what would cause a check engine light to come on

While your car can't talk, it communicates with yous using chimes, icons, and messages. 1 icon that you should never ignore is the orange, engine-shaped one that is usually constitute in the instrument cluster. It turns on when the car's onboard reckoner detects a problem.

Don't panic if you see it — information technology doesn't necessarily hateful you'll demand to give your side by side paycheck to the nearest mechanic. Problems that trigger a check engine light are sometimes basic and quick to gear up. Don't ignore it, either, and get information technology checked out equally apace as possible.

Here are the 10 most common problems that tin can trigger a check engine light. Keep in mind that the error lawmaking that caused the low-cal to turn on in the outset place is stored in your car's onboard reckoner, and yous tin can retrieve information technology using a simple Bluetooth-powered device linked to an app to get a precise idea of what exactly is wrong under the hood. Doing this on your own will save you money in the long run.

Oxygen sensor failure

The oxygen sensor (sometimes called an O2 sensor) measures the amount of unburnt oxygen in a auto'due south exhaust arrangement. It sends data to the vehicle'south computer, which uses information technology to regulate the mixture of air and fuel that enters the cylinders. An engine will keep running even if an O2 sensor needs to be replaced, but it will burn down more than fuel than usual. In the long run, a bad O2 sensor tin harm components similar spark plugs and the catalytic converter. It may also crusade a auto to fail an emissions test.

On average, a quality O2 sensor will set you back about $175, but the cost of labor volition vary profoundly depending on the vehicle's make and model, as well as your geographical location. Finally, keep in mind that most late-model cars have more than one O2 sensor.

Loose fuel cap

A loose fuel cap is one of the about common reasons why the check engine light turns on. The cap is a crucial part of a auto's fuel delivery system. Information technology notably prevents gasoline fumes from leaving the fuel tank, and information technology helps keep the whole organisation under the right force per unit area.

If your check engine calorie-free turns on immediately after a fill-up, pull over and make certain the cap isn't loose — or still on your automobile's roof. Sometimes the cap needs to be replaced, just it's not a trouble that's going to striking your wallet hard. Most auto parts stores comport universal-fit gas caps that cost somewhere in the vicinity of $15.

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Catalytic converter failure

The catalytic converter is integrated into a vehicle's exhaust arrangement. It turns the carbon monoxide generated during the combustion procedure into carbon dioxide. It's a fairly simple part, and its failure can often be prevented. That'due south good news because a new one costs betwixt $200 and $600 depending on the make and model. Every late-model car that runs on gasoline has a catalytic converter.

Performing regular maintenance (such equally oil changes) on time is key to keeping your motorcar'southward catalytic converter in working order. If you alive in the city and mostly bulldoze curt distances, take your car on the highway every at present and then to ensure the catalytic converter doesn't get clogged. And every bit always, go on your eyes and ears open for unusual sounds or discolored fume coming from the frazzle.

Spark plug/ignition coil issues

Put just, an ignition scroll generates the electricity the spark plugs need to ignite the fuel and air mixture in the cylinders. Classic cars have a single whorl, simply many mod vehicles apply one coil per cylinder (it'south often called a coil pack). If your ride has a V8 under the hood, you could have viii dissever coils. The monstrous Bugatti Chiron has sixteen. No thing how many you have though, a malfunctioning coil will almost certainly trigger the check engine calorie-free, only recollect, if your car burns diesel, you have neither ignition coils nor spark plugs.

Speaking of spark plugs, worn or fouled plugs can crusade a variety of issues including an engine misfire and hesitation under heavy acceleration. A worn coil can exhibit the same symptoms, and it can cause the car to shut off unexpectedly. A quality spark plug costs betwixt $10 and $20, while a coil is mostly in the $50 range. Changing your own spark plugs is also easier than it sounds.

Bad spark plug wires

As its name implies, a spark plug wire transfers electricity from the curlicue to the spark plug. Without it, the fuel and air mixture in the cylinders wouldn't ignite. The vast majority of cars use a single wire per cylinder, just in that location are models — notably, some older Mercedes-Benzes — with two spark plugs per cylinder and, consequently, two wires. Continue in mind that well-nigh newer cars do not use spark plug wires, however.

Symptoms of bad spark plug wires include a rough idle, a noticeable driblet in engine performance, and lower gas mileage. Expect to spend about $50 on a set of plug wires. Swapping them out is easy — information technology takes a few minutes and requires no special tools or knowledge.

Mass airflow sensor failure

The mass airflow (MAF) sensor monitors how much air enters the engine. It'due south a part of the engine-management arrangement, then your car wouldn't exist able to accommodate to changes in altitude without information technology. Symptoms of an MAF failure include a rough idle, trouble starting, and a sudden change in the position of the throttle pedal. Reduced gas mileage and stalling can too indicate a MAF trouble.

A MAF for a belatedly-model car typically costs betwixt $120 and $150.

Bug with an aftermarket alert

An aftermarket alarm system can wreak havoc on your car if it's not installed properly. It can drain the battery, trigger the check engine lite, or even prevent the vehicle from starting. So, when you least look it, it'll go off in the middle of the nighttime because a leafage from an oak tree roughshod on the hood.

If the above bug sound familiar, yous'll need to have the warning fixed, reinstalled, or replaced entirely by a competent mechanic. Getting information technology done right in the commencement place might cost a footling bit more, but the peace of mind that comes with having a fully functional alert is priceless.

Vacuum leak

Every machine has a vacuum system that performs a wide diversity of functions. The brake booster is vacuum-operated, and the vacuum system also helps lower emissions by routing the fumes as gasoline evaporates through the engine. If your machine's idle begins to surge or settles at an unusually high rpm, a vacuum leak could be the culprit.

Vacuum hoses can dry out and crack as they age, especially if they're exposed to intense estrus or extreme cold. This is the almost common crusade of vacuum leaks. Other mutual issues include croaky fittings and loose connections. Vacuum lines price simply a few bucks each, but tracing the source of the leak tin can be time-consuming — and expensive if you're non performing the piece of work yourself.

Exhaust gas recirculation valve failure

The exhaust gas recirculation (EGR) system lowers the amount of nitrogen oxide that comes out of the car'southward engine and helps it run more efficiently. It directs the hot exhaust gases back into the combustion chambers, which makes fuel easier to burn down. It also reduces emissions.

The EGR valve can go chock-full or neglect entirely. If you're even slightly mechanically inclined, y'all can remove the valve, clean it, and reinstall it in a relatively short amount of time. If the valve needs to be replaced, wait to pay at least $125 for a make-new, OEM-quality unit of measurement.

Dead battery

The battery is every bit simple as information technology is of import; without it, your automobile won't start. Today'due south batteries terminal much longer than before and they're maintenance-costless. The price of a new i depends on the type of car yous drive, but plan on spending at to the lowest degree $100 for a quality bombardment.

Changing or charging a battery on your own is a relatively like shooting fish in a barrel task, but keep in listen that in some late-model cars, information technology's buried under countless plastic covers, and it might be a picayune difficult to access. Also, note that disconnecting the bombardment volition often reset your stereo system. If you don't have the lawmaking, enquire your local dealer for it before you unbolt the positive and negative terminals. Otherwise, yous'll be driving in silence.

My check engine low-cal is on. At present what?

Modern cars are brimming with loftier-tech bells and whistles, but you inexplicably nonetheless demand a split up, aftermarket device to decipher why the cheque engine low-cal is on. Most motorists simply have their car to the dealership. That'south the easy way out, only it's also the most expensive road to have. If you want to skip a trip to the repair shop, spend a few dollars on a Bluetooth-compatible OBD II scanner (or a more avant-garde adapter) and download a compatible app similar Torque from either the Google Play Store or Apple's App Store. You can get the tool and the app for less than $15, which isn't bad considering many shops charge between $50 and $100 to pull codes from the ECU.

Ready? Commencement by finding your car'due south OBD II port. It'due south normally in the driver'due south footwell, not far from the hood release, but sometimes it'south hidden backside the centre console or in a compartment built into the flooring. Plug in the scanner, launch the app on your telephone, and the error codes stored in the machine's ECU will appear on the screen. Sometimes the codes are clearly explained; other times, you'll demand to do a bit of searching to figure out what something like P1301 means. Repair manuals are useful for deciphering codes, but Google usually has the answer.

Error codes are a useful diagnostic tool that tin can help you figure out where to start when your automobile needs a repair; merely be careful to sympathise their limitations. Error codes don't always tell the full story.

Once, when working on a relative's motorcar that had lost all power, the ECU codes indicated a problem with the turbo. But the event wasn't with the office itself — it was a cracked vacuum hose. Long story curt: Having a list of codes at your disposal doesn't e'er hateful a straightforward solution. You may need to spend a few minutes (or, at worst, a couple of hours) poking around the engine bay to detect the issue.

There are professional-grade code scanners that are more precise but besides much more expensive. The scanner can only give you a code; you also need in-depth knowledge of what each lawmaking ways or a useful way to find out. Alternatively, some automobile parts stores will run a diagnostic examination for costless. Even so, getting a Bluetooth scanner and an app will save you time and coin while making you more car-savvy. Brand sure the unit you selection is uniform with your car before buying it. Some cheaper scanners won't work with every brand and model, so information technology pays to do your research.

Volition the check engine light tell me when I should fix my motorcar?

The check engine light provides an idea — sometimes precise, sometimes vague — of what'southward wrong with a car. However, information technology does not supersede a skilled mechanic or routine maintenance.

In other words, don't expect until the check engine light comes on to get your machine maintenance washed. The ECU will not warn you lot that the water pump is most to neglect, that ane of the brawl joints is worn, or that the A/C volition finish blowing cold air in mid-August. Many people remember that the check engine light serves the aforementioned purpose as a check-up reminder when it really alerts yous that yous're probably due for a repair. By that point, the impairment has already happened in many cases.

You can think of car maintenance as a two-stride process. The first and near critical is routine, preventative maintenance. You should exercise these tune-ups on a schedule and not in response to whatever problems. The 2nd is timely diagnostic maintenance which is responsive to changes like new sounds, smells, or feelings equally you drive.

You also want to exist familiar with your car's basic needs, similar how often to change the oil and coolant or replace brake pads. A picayune enquiry into your specific vehicle and basic mechanics can salve yous fourth dimension and money in the long run. If you're consistent with a regular maintenance routine, you may never see that little orange engine light pop on at all.

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