That Pesky Check Engine Light and the Code Reader

That Pesky Check Engine Light and the Code Reader By Grace Abbasi

Spending from $45.00 to $100.00 for an OBD2 Code Reader could save you hundreds of dollars in repair costs. Best of all the code readers are easy to use. The OBD2 Code Reader package has an instruction book that tells you how to use the OBD2 Code Reader and definitions for the codes.

When that pesky "check engine" light comes on and you take the car to the repair shop to see what the problem is, the auto mechanic will read the code and tell you that a part needs to be replaced or a repair needs to be done, depending on the code reported, when this is not always the case. The fee that the repair shop charges for this service (attaching their OBD2 code reader to a vehicle to read the code) usually is the price they paid for their OBD2 Code Reader.

Nice deal for the repair shop, every time the auto mechanic reads the code on a customer's vehicle they get reimbursed the cost of their OBD2 Code Reader. What is wrong with this picture?

As many times as not, a code detected by the on-board computer can be caused by a momentary or temporary situation in the engine, which does not necessarily need repair.

So ask yourself - "Do I want to pay the fee at the repair shop to have them read the code that made my check engine light come on? OR just get my own OBD2 Code Reader - pay for it one time and use it as many times as is necessary and save money?"
Read the instruction book that comes with your OBD2 Code Reader
for complete instructions.

Briefly --> how to use the OBD2 Reader

If your "check engine light" is on, plug the OBD2 code reader into the receptacle, typically found under the steering wheel, and refer to the code reader book to find out what the code means. We recommend that you erase the code and if the "check engine" light comes back on within a few days, with the same code then, more than likely, repairs should be done.

Example: Just last week - it happened to us - That pesky "check engine" light came on after I had just filled the gas tank after letting it get down to 4 gallons. We put our code reader on it and the OBD2 gave a code of P0153 - 02 Sensor slow reaction.

When allowing the gas tank to get that low on gas the engine probably picked up some moisture from the bottom of the gas tank. We erased the code and it has not come back on since. If it had NOT been a temporary problem, within a day or two, the "check engine" light would have come back on with the same code.

Had we taken the car to the auto repair shop they would have charged us to read the on-board computer for the code and, possibly, parts and labor for the replacement of the 02 Sensor. We saved approximately $200.00, by having our own OBD2 Code Reader, erasing the code and waiting to see if the "check engine" light came back on.

However, after a week the check engine light has not come back on, telling us that this was a temporary situation and replacement of the 02 Sensor is not required.

When the "check engine" glows red on the dashboard, we make a practice of reading the code, making a note of the code reported and erasing it from the on-board computer. Wait a day or so to make sure the "check engine" light doesn't glow red at us again which indicates a temporary situation. If the same code returns then we would resolve the situation with whatever repairs are required.

This event is testimony to the fact that the cost of $60.00 (in our case) for our OBD2 Code Reader more than paid for itself with only one use.

Engine Light Nightmares

Engine Light Nightmares By Don Stevens

It's hard to imagine, but sensible guys and gals out there actually go nuts whenever the check engine light goes on. They faithfully take their car or truck to their loyal mechanic. No one really knows what happens when it's there; the mechanic will inspect it and probably tell you it needs something that you've never heard of, or didn't think existed for your model.

Let's face it, everyone's busy and cannot possibly check their mechanic's credentials, and scrutinize everything in his to do list for your car, but don't be a fool. There are a lot of legitimate mechanics out there but there's a lot who let's say are over imaginative when it comes to inspecting what's wrong. Maybe you are mechanically inclined, and are able to open the hood and take a gander. If you know what you're doing fine, but what if you're not sure? If only you had a friend to tell you what's wrong, and what's not wrong. Someone who will keep your questions to himself, and won't shame you in front of others when your check engine light does come on and you have no idea how did it happen.

If you're mechanic is your friend, then that's fine. But do you actually want to waste his time and your money to do something that was so simple that could be solved in a few minutes? What if I were to tell you that simple questions can be answered in minutes by online car repair question sites, such as Automotive Experts Online. They can save you time and money. Before you yell, How can a website fix your car? Well, as much as the internet has grown, it cannot actually fix your car, just like the web cannot actually take a test for you to help you get a passing grade. But remember, the information highway can give tons of information to help you pass that test yourself. Sites like these are the weapons of choice for average car owners, or weekend mechanics as well. Answers to common car repair questions, such as "What should I do when my Honda Accord check engine light goes on", or "resetting my Toyota check engine light" can be found in a jiffy.

Here's how a site like this works. Let's say that your check engine light is on and you don't know why; so you go online and ask. Incredibly, most of the time, the engine has nothing to do with the light that gives you warning. In minutes a trusted authorized mechanic will be there to answer any questions and give you support. Here is a sample of what may happen: when a check engine light comes on, a board stores a code that will lead to where the malfunction is located. Just like a map with the treasure being your malfunction, the root to your problem. It doesn't necessarily show you exactly what is wrong, but it gives you a code that you (or a technician) can decode to fix that problem. Sounds simple, doesn't it? All you have to do is get all your facts straight by doing a little research. Here's another example: let's say the code p0171, oxygen sensor indicates lean" shows up, making the check engine light appear. This doesn't mean the oxygen sensor is bad, but that the oxygen sensor is stuck lean. There could be a number of reasons for this: the oxygen sensor is lazy, or may actually need to be replaced.

Sites like Automotive Experts Online have a database to search for free. You can give your own questions a try. Certified auto technicians are there to help you with all sorts of car problems, such as check engine lights for Honda Accord or Toyota check engine light, or even help with jumpstart a car. This is safe and reliable auto advice that's also cheap and fast. Who has time to figure out common car problems on their own, and auto mechanics can charge up to hundreds of dollars to tell you what's wrong before fixing it. Sites like these are great for car owners who do the work themselves, but can be a life savor for newbies who have been afraid to fix their cars.

The site is free to register and join, so try logging on today. Questions can be seen for free and registered users bid on answers written by real certified experts who are there waiting for your questions. Quick questions relating to Toyota check engine light, or check engine light for Honda Accord are often answered within minutes. You are also guaranteed your satisfaction with a full refund your deposit 100% if you are not satisfied. Pretty good service for when you're in a pinch.

Check Engine Light and Car Maintenance

Check Engine Light and Car Maintenance By Matt Brooks

Is your "Check Engine" or "Service Engine Soon" light on? If so, you may need to "service your engine soon," but how can you know for sure what is wrong without taking it to a dealership and getting charged for a diagnostic test. The car still runs fine, so what's the big deal.

There are a wide range of things that can trigger the unwanted light. It can be anything from a misfiring cylinder due to a bad spark plug, to a bad O2 sensor, to an air fuel ratio outside the optimal parameters. There is an easy and cheap way to check. In our area of georgia, I have found that most of the Autozones carry the OBD1 and OBD2 diagnostic computers which can scan for trouble codes. They offer this as a free service to their customers, which can save the $35 to $80 I have seen charged for the same thing.

Once these error codes are received from your computer, you have a clue as to what the problem is. You can now do a simple google search to see what the codes mean specifically for your vehicle. In a lot of cases, it will tell you exactly the faulty component, such as which O2 sensor or cylinder is failing. You can now purchase the parts you need and save time and money on the repairs and service.

Beginning in the 1990's most cars began coming equipped with on board diagnostics, or OBD codes. Also called trouble codes, these codes help diagnosis problems your vehicle is having, sometimes before they are bad enough for you to be stuck on the side of the road. If the warnings are acted upon, you can save yourself in the long run. There are two different types of on board diagnostics depending on the make and year of your vehicle. OBD 1 cars were produced up to '95 and OBD2 runs from '95/'96 and up. Check your vehicle owners manual to know for sure.

When your check engine or service engine soon light come on, be sure to go and have the codes read. Don't wait for your car to stop running before you take it in for repairs, because the cost of waiting is usually higher.

To check your trouble codes, you can visit one of my favorite sites for trouble code information located at the code database. Here you can find all the codes for all makes and models sorted by year and code. Armed with the right info, maintenance and service are a breeze for any vehicle.

Hopefully you have some useful information to use when you encounter the dreaded check engine light. Stay up to date on the maintenance and service and your car should return the favor by being reliable.

OBD II 101

OBD II 101 By Jason Helferich

February 2005

OBD-II. I’m sure everyone has heard of the word or abbreviation. What exactly is it? What does it do? All cars currently being built use this system and today we will go into detail to show you what it is, how it works, and if it inhibits or promotes modifications to your car.

OBD-II stands for on-board diagnostics and they are standard on all vehicles manufactured today. In the late 1970s, auto manufacturers began using electronics or computers to monitor and control powertrain functions. This was done as a way to control emissions on new cars to comply with government standards. OBD-II is a set of standards and practices created by the Society of Automotive Engineers (SAE), which was approved by the EPA and CARB for implementation by 1/1/1996. Every car built since 1/1/1996 has OBD-II and actually manufacturers began implementing it on certain models as early as 1994. Some of these vehicles were not 100% compliant, but it was a way for the manufacturers to begin getting acquainted with the new system.

The computer reports to the driver if it encounters a “problem”. The “problem” is relayed to the driver by way of a MIL. MIL stands for malfunction indicator light, commonly known to drivers as the “Check Engine” light. There are three types of signals the computer will send to notify the driver. The light will flash occasionally if a momentary problem occurs. If the light comes on and stays on, this is a more serious issue and most likely will affect the emissions or safety of the car. When the light starts flashing, this is evidence of a serious problem and the vehicle should be taken to a repair facility immediately. The powertrain control module, or computer, will store the conditions the vehicle was experiencing when the error occurred; this is known as a “freeze frame.” The “freeze frame” will store the speed, tachometer speed and other data to help the technician see what type of driving the car was experiencing when the error occurred.

The creation of OBD-II makes it easier on the technician and repair shop. Instead of needing multiple scan tools to diagnose vehicles, they are able to use one with multiple software. Older vehicles have the diagnostic connector in various locations such as under the hood, under the carpet, or under the dash. Reading the codes was different on older vehicles, on 80’s Chrysler vehicles you had to cycle the key off-on-off-on-off-on and the Check Engine Light would blink to signify the codes. On Honda’s, you had to lift up the passenger side carpet and watch the blinking LED on the computer to get the codes. With OBD-II, the diagnostic connector is the same and is always located on the driver side under the dash.

In the early days of OBD-II, many performance enthusiasts were afraid that the OBD-II system would not allow for the modification of the engine to the specs and power that they desired. It may have been the case had it not been for the intervention of SEMA. SEMA worked with the manufacturers to develop the program, therefore protecting their industry. OBD-II is designed to allow cars to run cleaner and more efficient and it does just that. Newer cars emit less emissions and have more horsepower than cars before OBD-II.

In the current market there are also products available through the aftermarket that will allow owners to check their own codes and view the data list themselves. These products were created to save the consumer money as repair shops charge a labor charge just to hook up the scan tool and view the diagnostic trouble codes. One such product is the AutoTap (www.autotap.com), which makes a program for Windows or for your Palm Pilot. This software allows the user to view sensor data in real-time to know what their car is doing at that moment.

If my Check Engine light is lit, is my car losing power? The answer is no. Check Engine light will primarily light if the PCM recognizes an error that will cause an emissions problem. These errors will not alter the fuel, spark or boost of the vehicle; therefore you may not experience a drivability problem. OBD-II can also keep your vehicle drivable in problem situations known as limp-home mode. In the old days, if a misfire occurred, fuel being dumped in the exhaust and not being ignited would wreak havoc on the catalytic converter and cause it to overheat. With OBD-II, the PCM can recognize the misfire and shut off fuel to the injector to prevent damage to the converter. On OBD-II systems there is a data table that the PCM will use to determine fuel, spark, timing, etc. It uses inputs from various engine sensors to control this mixture. In this system, if one sensor goes bad the data table can eliminate its input from its formula and use a base setting to determine the fuel and spark settings.

Aftermarket products can cause for Check Engine lights to light. This is only caused by products improperly installed or manufactured. We have heard stories about the Check Engine Light illuminating when swapping out exhausts or intakes, but these codes being set will not affect your power output. This is typically caused by the premature release of a product without the proper research and development.

Let’s take a look at how an actual OBD-II code breaks down. A sample OBD-II code is P0105. Each digit in this code means something. The first digit is the system: P for Powertrain, B for Body, C for Chassis and U for Network. The second digit is either a 0 or a 1. The zero is an OBD code, one is a proprietary code. The third digit is the subsystem of the main system, in this case the powertrain: 1 is for fuel/air metering, 2 is for fuel/air metering(injectors), 3 is for ignition system, 4 is auxiliary emission control, 5 is for computer output, and 6 and 7 are for transmission. The last two digits signify the fault code. Therefore, this code is a powertrain code, an OBD code, subsystem is fuel/air metering and the 05 is the fault code.

Today, we have covered many of the basics related to the OBD-II system. Now you know how the diagnostic system in your vehicle operates. So next time your car has a Check Engine light on, you will know the story behind it and how to check and clear it if you so desire. If you have further interest in this system, please view www.obdii.com.

Self Diagnose Your Car And The Check Engine Light

Self Diagnose Your Car And The Check Engine Light By Andre Zayas

Even for the most mechanically inclined, determining exactly what is going on with your car behind the check engine light can be very complicated. Some people are willing to hunt out the problem through trial and error while others will be quick to drive their car to the mechanic to get the diagnostic test run and then take the car home to resolve the issue themselves. Either way, this can be a costly process. There has to be an easier way.

Why the Check Engine Light is On

No one likes to think of having to take a trip to the mechanic each and every time the check engine light comes on. In the last ten or so years, cars have been designed so that this light will come on for just about every problem imaginable, not just because the engine needs some type of repair. A problem as simple as the gas cap not being tightened enough last time you went to fill up your car can cause the light to go on. This makes the light almost impossible to decipher without the use of a computer device.

Car Error Codes

In your car's computer, all problems will register as a code. If you were able to extract these codes from your car's computer and decipher them for yourself, you will know what needs to be done to have your car running smoothly again. So why would you spend hundreds of dollars to find out what is wrong and then spend the money to fix it yourself when you can diagnose the problem yourself?

Codes Explain the Check Engine Light

These problem codes that register through the check engine light are the answer to all of the problems that could possibly occur with the car. Extracting these codes will tell you exactly what is going on with your car and you will be able to figure out what exactly needs to be fixed rather than swapping out part after part until the issue has been resolved. Not only can you cause more damage to your vehicle by swapping out parts but you will also spend unnecessary money on parts that it turns out you do not need.

Working as your own mechanic can definitely have its advantages. You will be able to save yourself the high cost of labor as well as the time that a mechanic might take. Many other people also use mechanics so if you need to use one, you will likely need to wait your turn, but it could be worth waiting to find out why the check engine light is on. When you do it yourself, you can work when you have the time.

What Does the Check Engine Light Really Mean

What Does the Check Engine Light Really Mean? By Andre Zayas

When a car's check engine light comes on, it is a mystery to most drivers. It instills panic in many for good reason. There are times when that light can mean drastic problems in a car's engine system or other operating parts. There are also times when it simply means you changed your brand of gasoline and the car needs to adjust to the new mix. For that reason there is a tendency to ignore that little light and hope the problem will go away.

Should You Worry About Your Check Engine Light?

How do you know if the check engine light is trying to tell you there is a serious problem or if it is nothing to worry about? One way is to take the time out of your busy schedule, drive to the mechanic and pay a hefty fee to have them hook up their machine to your car's OBDII system and then tell you to tighten your gas cap as a result. Or you can get your own OBD diagnostic tool that will give you all the information you need right at your fingertips.

Onboard Diagnostic System

These simple devices attach to your automobile's OBDII (onboard diagnostic system) right under the dash just like the big machine at the mechanic shop does and it will give you the exact same readouts plus provide easy to understand graphs and explanations of those confusing codes your mechanic gives you to keep you in the dark as to what is really going on.

Simply take the OBD diagnostic system for a short ride with you when your check engine light comes on and then take it in the house to your personal computer and download the data. The website provided to you with your OBD diagnostic system will decipher the information and give you all the information you need to determine if the problem is serious or not at fractions of the cost of a mechanic's garage. The readout will also give you simple solutions to the easier fixes if they are available plus if you do need to take the car to your mechanic, you can go in well-armed with the knowledge you need to keep from being overcharged for their services.

The OBD system will also alert you to potentially damaging driving habits you may have acquired over time even when your check engine light is not blinking. Things like hard braking and excessive acceleration so that you can correct problems before they affect your car's mechanisms.

Benefits of OBD

There are even more benefits to your own OBD diagnostic system. Never get stuck with a lemon again by taking it on all of your test drives. With your own diagnostic system, you will be able to find out for yourself if your potential new or used car is in good operating order before you drive off the lot. You can even find out why the check engine light is on. You can also take all the worry out of vacations when you hook it up before a road trip.

Reset the Check Engine Light

Reset the Check Engine Light By Mark Gittelman Mark Gittelman Level: Platinum Mark Gittelman is an ASE Master Mechanic and a member of the society of automotive engineers. Mark has more than 24 years of outstanding service ... ...

If you disconnect your battery to reset your check engine light. You may erase valuable memory from the computer and wind up disabling your car stereo and factory installed alarm.

First, why is your check engine light on? The check engine light or service engine soon light is directly connected to your car's computer and monitors the emission system. This warning light was federally mandated by our government to notify the driver that the vehicle may be polluting the atmosphere.

The check engine light is all about the war on pollution, global warming and smog. One of the main problems with this emission system-monitoring device is that it is very sensitive. Often you will find that this light is illuminated for a minor malfunction or even an intermittent problem.

This is why the first step in the solution to the problem is to clear the code and retest the vehicle to see if the light returns. The problem with this is that the fastest way to reset the check engine light is to disconnect the battery. But there are many systems in your vehicle that require constant battery power.

Most people do not realize that your vehicle computer adapts to your driving habits. Your vehicle computer stores memory functions such as shift points, idle speed and throttle position for the primary driver. When you disconnect the vehicle battery you wipe out this memory and the computer returns to a default mode, which may make the vehicle run in a manner that you are not accustomed to.

Other complications that may arise from disconnecting battery power to your vehicle may include that the radio will not work after you reconnect the battery. Most vehicles today have theft protected radio systems. When you disconnect the battery the radio thinks that it is being stolen. Re-activating the radio can be a lot of trouble, and in most cases includes obtaining the code from the vehicle manufacturer to reactivate the radio.

Another common problem you may run into by disconnecting power from the vehicle is that many vehicles today have a factory installed alarm system. When power is removed from the system. The vehicle can go into a lock down mode to prevent engine startup in case the vehicle is being stolen.

It is a very common problem today to have your check engine light pop on for little or no reason. Every vehicle owner should learn how to reset the check engine light for this reason.

The best way to handle the reset of the check engine light is to purchase an auto scan tool and clear the code without disturbing the battery connection. Automotive scan tools have really come down in price and make this the best way to approach the problem of resetting the check engine light.

Turning off the check engine light with an auto scan tool requires no technical experience and is very easy to accomplish. After the reset the check engine light procedure is performed if the light stays off you have just fixed car in less than 10 minutes. If the light does come back on you now have the knowledge necessary to get the problem repaired quickly and easily.

Inside the Check Engine Light

The Devil Inside the Check Engine Light By Frank Bellucci

You know that funny little red light that comes on that says "Check Engine". We've all been there, minding our own business driving down the road and "pop" it comes on without any regard to our schedule and our busy lives. I don’t know about you, but I’ve noticed over the years that it has a reckless indifference to how stressed I am on a given day.

Long ago, I used to think the Check Engine Light meant something like the engine was about to explode or something. Panicking, I’d call my service advisor and report that somebody needs to “check my engine” because the car said so and it was after all a “red light”. I’d beg for an emergency landing strip and to clear all traffic from my airspace so I could immediately descend into the shop for an emergency car version of cardiac arrest surgery. I’d expected them to have fire extinguishers and ambulances at the ready to help.

Later my grandfather (picture the aging 80 year old Italian guy in the Godfather) told me that the light was actually only put there by crafty carmakers that just wanted to make sure you took your car in so they can make money on some kind of service.

Well, today I can tell you the reality may be a bit less extreme than either of these scenarios. The problem identified by the Check Engine Light may be quite uneventful and not nearly so death defying. But it can also mean something serious and should be checked out as soon as you can. It may save you some big bucks. Your trusty mechanic should be able to hook your car up to his shop computer and tell you what the car is griping about. Your car has an on board diagnostics module which discovers and records problems it sees from potentially hundreds of points in the car.

I guess in the old days, before car computers, the car would just brake down and you’d have to tow it in for service. The Check Engine Light and the accompanying computer sensors actually try to prevent such an occurrence by observing and informing you of an anomalous condition it sees.

So Grandpa wasn’t exactly right. It wasn’t the carmakers trying to make sure you visit the service shop more often. It was actually designed to keep you on the road and give you some reaction time between a potential problem (or actual one) and a more costly problem or breakdown.

So hopefully that helps give a little background to your Check Engine Light condition you might have and why it’s happening! Thanks for reading!

Check Engine Light Goes On

Check Engine Light Goes On By Naum Levinson

What to do if the "check engine" light goes on?

It does mean that you should get the car checked out
as soon as possible. If you ignore this warning, you
can damage some expensive components, and get poor
gas mileage.

What this light is trying to tell you?

This light is a part of the On-Board Diagnostic system (OBD II)
The engine systems performance is being controlled and monitored by computer. When the computer finds a problem in
any system, it waits a little for the possibility that the faulty system
will correct itself. If this doesn't happened, the computer turns on
the "check engine" light. At the same time, the computer stores
a "trouble code" in the memory. This code identifies the system or component that is malfunctioning. Code can be read with the
special scanning tool.

If the "check engine" light turns "on", it will either blink or remain
solid, depending on the problem. The blinking light indicates a
serious problem that requires immediate attention. Most of the
time it an engine misfire. In this case, the unburned fuel
gets into the exhaust system where it can explode and severely
damage the catalytic converter. Repair will be expensive.
The solid "check engine" light indicates a non-emergency, but the
car or truck should be checked ASAP.

Tip: on late model vehicles, loose gas cap will trigger the "check
engine" light. The first thing you do, try to tight your gas cap first.
After a while, the light will turn off but the trouble code will remain
in memory.

My Check Engine Light Comes On Then Goes Off

My Check Engine Light Comes On Then Goes Off Sometimes - This Is Driving Me Crazy By Austin Davis

Reader Question Thursday driving my 2001 Hyundai Sonata GLS check engine light is on and car sputters near my home. I take it home and checked & was low on oil. I take my husbands car to go buy oil and put it in. I tell my husband about it, he takes it to nearby store no problems, no check engine light.

Friday I drive it as normal; probably about 30 to 50 miles for the day. No check engine light and no problems.

Saturday ran all day from here to there no check engine light and no problems, then I bring home the family and go out to finish some shopping when on my way home I think I hear sputter again.

Go to turn down radio at which time car sputters again, then jerks check engine light comes on again but I get it home without incident after that. Decided would take it in after the holidays, moved it on Sunday from where it was parked started as normal. Husband said start it every so often. Next time maybe Monday or Tuesday tried to turn over once then after that not much turn over.

This Tuesday jumped it with my husbands car. Was hard to get jumped but finally did. Went out couple hour later started again no problem and check engine light no longer on.

Started Wednesday no check engine light and no problem.

Started today (Thursday) no check engine light and no problem.

Can this be as simple as a bad cell in the battery? I don't want to put a new battery in if something is draining the battery. What is your opinion of these symptons?

Thanks for your help,
Judy

Hi there Judy,

Thanks for your email. I really think you might have two problems...which was just coincidental. If the battery was original to the car, it was time for a new one. Five years is the MOST I have seen out of the life of a car battery. So you were probably past due there.

The check engine light issue, have you read my article on that? I would suspect you might have an engine "miss" (since you said you felt the engine jerk) from a worn out spark plug or spark plug wire or something along those lines. If the engine has over 50,000 miles I would say have your mechanic check to see if you need a tune up.

If the engine miss-fires (from needing a tune up) the computer onboard will signal the yellow check engine light to come on to indicate a problem has occured. I am assuming you are talking about the yellow light not the RED engine light...correct?

It is perfectly normal for the yellow light to come and go if there is an intermittent running condition, and low oil is usually not something that affects the YELLOW light to come on. That yellow light is like an emission light, it is looking to see if the engine is running at peak efficiency, and not polluting the air with too much exhaust from running poorly.

When an engine miss-fires or "misses" one or more of the cylinders did NOT burn the fuel that was inside the cylinder so that unburned fuel was pushed out the tailpipe which as pollution and your computer noted the problem and set the light to warn you of a potential problem. So, the yellow light is doing its job of reporting a problem with the engine.

The next day you get in your car...and it runs fine...no misfire and no "jerk" is present so no yellow light is seen on the dash. The next time the engine jerks...the light should come back on.

I would start with checking to see if you need a tune up first, and see if the "jerking" and check engine light issue goes away. If not, then have your mechanic dig deeper into what is causing the light to come on, but with intermittent problems like this your mechanic will probably have to catch it in the act to be able to properly diagnose it for you...which might be easier said than done.

The Mysterious Check Engine Light

The Mysterious Check Engine Light By Jason Miller Jason Miller Level: Platinum Jason is the webmaster for Red Hill Supply - Air Tools and More...

If you have had your car or SUV long enough, that annoying "check engine" light has probably made an appearance on your dash board. The first time I saw it, I popped the hood and "checked" the engine. It seemed ok to me. My car was running fine. So like most experienced car drivers, I ignored it or I tried too. The really insidious thing about that little innocent light is that it really gets to you after a while. After a long drive at night with that light shining at me like a laser beam, I considered putting it out its misery with my tire iron. Which brings up the question, what is it there for. Well here is a basic answer.

The "check engine" light is connected to the car's engine fuel management computer. This is the computer that runs the fuel injectors, reads the engine sensors, etc. The oxygen sensors are used by the ECM to determine how accurately it's injecting the fuel, and adjusting the way the fuel is injected to compensate for changing conditions. When the computer inside the ECM detects that there is something wrong, the ECM turns on the "check engine" light. For example, a bad sensor or engine operating parameter that exceeds a preprogrammed set point then the ECM turns on the light to let you, the driver, know that something is wrong and needs to be corrected. It doesn’t mean something cataclysmic is about to happen, just that the computer that runs a lot of the functions in your engine is getting some bad information. Most of the time this means an oxygen sensor has failed and needs to be replaced. In a lot of states, your car will not pass the inspection when the light is on. So you have to fix it before you can get a new inspection sticker.