AUTONET TV

How Your Check Engine Light Works

Have you ever had an experience like this in Du Quoin, IL? You drive through the one of those automatic car washes. When you get to the end, where the dryer is blowing, your Check Engine light starts flashing!

You fear the worst, but within a block or two, the light stops flashing, but stays on. By the next day, the light is off.

You wonder; "What was going on?" Well, it's actually a good lesson in how the Check Engine light works.

Your air intake system has a sensor that measures how much air is coming through it. When you went under the high-speed dryer, all that air was blasting past the sensor. Your engine computer was saying, there shouldn't be that much air when the engine is just idling. Something's wrong. Whatever's wrong could cause some serious engine damage.

Warning, warning! It flashes the Check Engine light to alert you to take immediate action.

It stopped flashing because once you were out from under the dryer, the airflow returned to normal. Now the engine control computer says the danger is past, but I'm still concerned, I'll keep this light on for now.

Then the Check Engine light goes off in a day or two.

The condition never did recur, so the computer says whatever it was, it's gone now. The danger is past, I'll turn that light off.

Now a flashing Check Engine light is serious. You need to get it into McPherson Automotive as soon as possible. But if it stops flashing you can wait a few days, so you have time to see if the problem will clear itself or if you need to get it checked. How does the computer know when to clear itself?

Think of it this way. The engine control computer is the brain that can make adjustments to manage the engine. Things like alter the air-to- fuel mix, spark advance and so on. The computer relies on a series of sensors to get the information it needs to make decisions on what to do.

The computer knows what readings are in a normal range for various conditions. Get out of range, and it logs a trouble code and lights up the Check Engine warning.

The computer will then try to make adjustments if it can. If the computer can't compensate for the problem, the Check Engine light stays on.

The computer logs a trouble code. Some people think the code will tell the technician exactly what's wrong.

Actually, the code will tell the technician what sensor reading is out of parameters. It can't really tell him why, because there could be any number of causes.

Let's say you're feeling hot. You get your heat sensor out – a thermometer – put it under our tongue and in a minute or two you learn that you have a fever of 104 degrees F (40 degrees C).

You know your symptom – a fever – but you don't know what's causing it. Is it the flu, a sinus infection or appendicitis?

You need more information than just that one sensor reading. But it does give you a place to start and narrows down the possible problems.

There are reports on the internet telling you that you can just go down to an auto parts store and get them to read your trouble code or buy a cheap scan tool to do it yourself.

There are two problems with that. First, the computer stores some trouble codes in short term memory and some in permanent memory. Each manufacturer's computer stores generic trouble codes, but they also store codes that are specific to their brand.

A cheap, generic scan tool, like you can buy online or that the auto parts store uses, doesn't have the ability to retrieve long-term storage or manufacturer specific codes. Your Du Quoin, IL, service center has spent a lot of money on high-end scan tools and software to do a deep retrieval of information from your engine control computer.

The second problem is that once you've got the information, do you know what to do with it? For example, a very common trouble code comes up when the reading on the oxygen sensor is out of whack.

So the common solution is for the auto parts store to sell you a new oxygen sensor — which is not cheap — and send you off on your way. Now your oxygen sensor may indeed have been bad and needed replacing. But the error code could have come from any of a dozen of other problems.

How do you know the right solution? Back to the fever analogy, do you need surgery or an aspirin? Leave it to the pros at McPherson Automotive. Give us a call and let us help you resolve your check engine light issue.

McPherson Automotive
1 E Park St
Du Quoin, IL 62832
(618) 542-9203
http://www.mcphersonautomotive.net

Stuck! (Vehicle Door Issues)

This may have happened to you.  You drive somewhere and get out of your vehicle only to try closing the door and it just won't stay closed!  What a helpless feeling.  You can't lock it; you can't leave it like it is. Or, let's say you head down to your vehicle to head out to work in the morning and you can't open the door.  What are you going to do now?

Vehicle doors take a lot of abuse.  They are opened and closed hundreds of times and we expect them to just keep working perfectly all the time.  They do require a bit of tender loving care.  Let's take a look at two different scenarios of stuck doors.

First: the door that won't close.  It's a security issue.  It's also a safety issue.  You can't really safely drive a vehicle with a door that won't close. What if you or a passenger is tossed out?  Sure, some people try to tie a stuck-open door closed or bungee it, but that's dangerous.  It's best to get that vehicle to the service repair facility as soon as you can, and having it towed is the safest way. 

Second: the door that won't open.  There are many reasons this can happen.  Freezing weather is one, a misaligned door is another.  There could be electrical issues.  Corrosion could have broken a part inside the door.  The possibilities, unfortunately, are numerous.

If you can't get into your vehicle's driver's door, with any luck another door might open and you can climb into the driver's seat and head on to the repair facility.  A lot of people may be tempted to try to fix a stuck door themselves, but many wind up causing more damage to the door and have to have a trained technician step in to repair the mess.

One way to minimize the possibility of having a door stick open or closed is to make sure it gets regular maintenance.  Door locks, hinges and latches should be lubricated at certain intervals.  Locks should be kept clean.  While many vehicles now have electronic locks, sometimes an electrical failure in the vehicle or key fob can inadvertently lock you out.  Nearly every vehicle has a mechanical key in case that happens; if you don't know how that works, have your service advisor show you how. 

Also, you technician can make sure your doors are properly aligned and aren't sagging. All of these things can help you keep your doors opening and closing the way they were designed to. Your next trip may "hinge" on your doors being in top condition.

McPherson Automotive
1 E Park St
Du Quoin, IL 62832
(618) 542-9203
http://www.mcphersonautomotive.net

Such a Little Part (Climate Control Resistor)

You expect your heater/air conditioner to work like it should.  You have a control for temperature and one for fan speed.  You even have a control for what vents the air comes out of. 

Don't be surprised one day if your blower fan develops a mind of its own and starts going crazy.  Most of the time, you may find that it starts blowing at full speed, and nothing you do to try to control it does any good.  This is what may be happening.

Your blower motor has an electronic component called a resistor.  It does what its name says; it offers resistance.  When you want the fan to run more slowly, you turn the fan speed down.  That resistor accomplishes that by turning its resistance up.  When the resistor fails, the power has nothing to slow it and the fan speeds up. 

It's a small part and can fail due to age or corrosion.  It's usually not an expensive part, either, but it's often found in a location that's not that easy for the technician to get to.  That means labor costs will vary depending on the design of your vehicle. 

Occasionally, a faulty resistor can cause the blower motor not to work at all or only partially come on.  But other things can cause that as well, such as a faulty fan switch or vent control. 

This is where a technician's training comes in.  Special equipment can track down precisely where the issue is so you can be assured the correct part is being replaced.

It's just not pleasant when the blower motor isn't following orders.  Have your service facility check it out so you can be the blower's boss, like it should be. 

McPherson Automotive
1 E Park St
Du Quoin, IL 62832
(618) 542-9203
http://www.mcphersonautomotive.net

Keep Your Cool in Du Quoin

Du Quoin drivers rely on their vehicle's coolant system to keep their engine cool. Coolant (also called antifreeze) mixed with water flows through your vehicle engine and absorbs heat. The mixture then flows out to the radiator where it's cooled by air flowing over the radiator. From there the coolant/water mix circulates back through the engine to absorb more heat.

There's a reason we mix coolant and water. Water alone actually does a good job transferring heat from the engine. The problem is that water boils at a temperature that's easily reached inside your vehicle's engine, so it can turn to steam which does not conduct heat as well and is harder to contain.

Also, if it's freezing outside in Du Quoin, the water in your engine could freeze while your vehicle is sitting out in the IL cold.

So, if you remember your high school chemistry, you'll know that a mixture has both a higher boiling point and a lower freezing point than either component alone.

Coolant, or antifreeze, is specially formulated to keep your engine safe in a wide range of environmental and operating temperatures in and around Du Quoin.

Whenever your vehicle is running, the coolant in the cooling system is working to keep your engine from overheating. When it's cold outside, the coolant acts as antifreeze to keep the fluid from freezing in your engine.

All that exploding fuel in your engine creates a lot of heat. Without coolant, the metal vehicle engine parts would expand so much that the engine would seize up and stop running. The parts could be broken or warp so badly they would have to be replaced. It could even be so bad that the whole vehicle's engine is ruined and has to be junked.

This is why it is critical that Du Quoin drivers check coolant levels frequently and have their vehicle's cooling system inspected for leaks. Also your vehicle has a maintenance requirement for draining and replacing your coolant. These recommendations can vary widely, so check your owner's manual or ask us at McPherson Automotive in Du Quoin.

The reason Du Quoin drivers need to change the coolant is that it has additives in it to protect the cooling system. As you can imagine, with all the heat, the cooling system's a pretty harsh environment. The additives keep the fluid from becoming corrosive and damaging the radiator and other vehicle cooling system components. Over time, the additives are depleted and the coolant just has to be replaced.

Many Du Quoin auto owners ask our advisors at McPherson Automotive why there are different colors of antifreeze. It is very important that you use the correct type of antifreeze. The different types of antifreeze – or coolant – are different colors so you don't mix them up.

They use different materials to make the cooling system, and they require different types of antifreeze to protect them.

So check with us at McPherson Automotive in Du Quoin or your owner's manual for the right kind because using the wrong coolant can void the warranty for your vehicle cooling system.

McPherson Automotive
1 E Park St
Du Quoin, IL 62832
(618) 542-9203
http://www.mcphersonautomotive.net