How Your Check Engine Light Works

Posted January 27, 2011 10:54 AM



Have you ever had an experience like this in South Windsor Connecticut? 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 started flashing!

You fear the worst, but within a block or two, the light stopped flashing, but stayed on. By the next day, the light was 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 our South Windsor Connecticut shop as soon as possible. But if it stops flashing, 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 you 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.

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 or that the auto parts store uses, doesn't have the ability to retrieve long-term storage or manufacturer specific codes. Your South Windsor Connecticut 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 are 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 Precision Motor Coach, Llc.. Give us a call at 860-282-1118 and let us help you resolve your check engine light issue.

Posted in the Dashboard


Breathe Deep With Your Cabin Air Filter

Posted January 20, 2011 9:54 AM



Bad air quality while you're driving around Manchester / Vernon is nothing to sneeze at. But seriously, more and more vehicles these days come equipped with a cabin air filter. Since they're fairly new on the scene, a lot of folks don't know about them yet.

These filters clean the air in the passenger compartment, or cabin, of your car or truck. They do the same job as the furnace filter you have at home. They can filter out particles as small as thee microns. By contrast, a grain of sand is about 200 microns.

So your cabin air filer can clean out dust, pollution, pollen and spores, to keep the air in your car nice and clean. And just like your furnace filter, they need to be replaced when they get dirty. Check your owner's manual, but they typically need to be replaced at around twelve to fifteen thousand miles.

The filter is usually either under the hood or under the dashboard. Some are a little tricky to get to, so you'll want to have your South Windsor Connecticut service center, Precision Motor Coach, Llc., take care of replacing them.

As we said, many people don't realize they have a cabin air filter and go to their shop complaining about a funky smell in the ventilation system. It turned out to be a cabin air filter that was long overdue for replacement – really dirty and starting to smell. A quick replacement and they were on their way and smelling fine.

People who are allergy sensitive can really benefit from a cabin air filter, as it keeps allergens to a minimum. If you're one of them, you'll want to stay on top of your filter replacement schedule.

Of course if you do a lot of driving in dusty or polluted conditions, you'll need to change your cabin air filter more often.

Posted in the Air Conditioning


South Windsor Customer Detective Work

Posted January 12, 2011 9:50 AM



One might say the most challenging part of being an automotive service technician at Precision Motor Coach, Llc. in South Windsor Connecticut is diagnosing a problem before it can be fixed.

Cars are made up of a bunch of complex systems. There usually could be a number of reasons for any given symptom. So it's challenging to track down the actual cause of the problem. And it can be frustrating for the vehicle owner because it can take time and money to get to the bottom of a problem. If it's not something obvious, it's easy for the customer to focus on the fixing and not the diagnosing.

Let us introduce you to something we'll call Customer Detective Work – that is helping your South Windsor Connecticut technician find clues to what's wrong.

We start with the detective basics: What, Where and When. Play along with me. You come in to Precision Motor Coach, Llc. and your car is making a funny sound.

  • Q: Where's the sound?
  • A: Around the right front wheel.

  • Q: What kind of sound?
  • A: Kind of a clunk, clunk sound.

  • Q: When do you hear the sound?
  • A: When I turn and accelerate.

  • Q: Right and left? Forwards and back?…

Do you see where we're going? You're gathering additional information to help your South Windsor Connecticut technician know where to start. Based on your car and the tech's experience, he'll know where to look and can start with the obvious suspects.

You can see how that would be more helpful than dropping the car off with a note that says "making a funny noise".

When you think you need to bring a vehicle in, make some notes about the problem. Rather than just saying "it's leaking", tell the tech the color of the fluid, and approximately where under the car you see the puddle.

Things like 'the car is stalling or sputtering' are often very hard to diagnose because they're intermittent. They may not happen every time you drive and usually aren't happening when you actually bring the car in. So, it is a big help for you to describe what's happening in as much detail as possible.

Your South Windsor Connecticut technician at Precision Motor Coach, Llc. will need to be able to duplicate the problem if possible so he needs to know details, like 'it stalls after it's been driven for about 20 minutes and I go over 50 miles an hour'.

If the tech can experience the problem personally, he's better able to make a diagnosis and repair. And, then test to see if the repair solved the problem.

Posted in the Service Standards


South Windsor Exhaust And Emissions Service

Posted January 4, 2011 11:04 AM



Sometimes when we talk about exhaust service in South Windsor, we think about exhaust pipes and mufflers. And if you can see smoke, or if it’s too loud. But, exhaust service at a place like Precision Motor Coach, Llc. is really a lot more comprehensive these days.

For example, in the U.S., the federal government mandated catalytic converters for all cars in South Windsor in 1976 and on-board emission control computers in 1990. Connecticut and federal emissions requirements have forced manufacturers to come up with much more sophisticated ways to comply with environmental regulations. Cars sold in Canada follow the same guidelines.

So, exhaust service has really become exhaust and emissions service. High-tech computer-controlled emissions devices are now a big part of that. And because it’s so sophisticated, your vehicle manufacturer recommends having your emission system checked out by a qualified technician, like the ones we have at Precision Motor Coach, Llc., regularly to make sure everything’s working right – which is usually every six months or 6,000 miles.

If your 'check engine light' comes on while you are driving around the Hartford area, especially if it’s flashing, then you need to get your car looked at right away. Chances are it’s an emission related problem. You might have exhaust or emissions trouble if your car is hard to start, runs rough, or if it’s noisy or smoking.

So let’s review the exhaust system. Everything starts with the exhaust manifold. That’s the part that attaches to the engine and collects the exhaust from the cylinders and directs it into the exhaust pipe.

The exhaust gaskets help seal the connection with the manifold and other joints along the way. Now, if the manifold is cracked or loose, or a gasket is leaking, then dangerous gases could escape into the passenger compartment, where you ride. Carbon monoxide can be deadly, so it’s important that your exhaust system doesn’t leak.

The exhaust pipes connect the various components. They can rust or be damaged by a rock, so they need to be inspected periodically.

Next comes the catalytic converter. This part actually looks like a muffler. It changes chemicals that are dangerous to your health, and to the local Connecticut environment, into harmless carbon dioxide and water. Now it doesn’t require any maintenance itself. But eventually they wear out. If it has, you’ll probably find out when your car fails an emissions inspection.

Now the muffler. Its main job is to quiet engine noises. Mufflers work by either absorbing or baffling sound. And you can actually customize your car’s sound with different mufflers – which is pretty cool because you can change the look of your car, and the way it sounds.

Rusted or road-damaged mufflers can actually leak and they need to be replaced right away. The exhaust system is attached to the car by a series of hangers and clamps that hold the system in place. And when these hangers come loose or break then hot exhaust components can touch and melt wires, hoses and lines. Just think of the damage a hot curling iron can do – but worse. It’s not good to have that waving around.

And finally, we end at the tailpipe. Appropriate name. This is the final outlet for the exhaust. And one other component is the oxygen sensor. It monitors the oxygen content of the exhaust so the engine-control computer can adjust the fuel-to-air mix to keep the car running right.

We hope this hasn’t been too 'exhausting' of a discussion, but these things impact everything from life and death safety due to exhaust leaks, to just fine-tuning the sound of your ride. And talk with your service advisor at Precision Motor Coach, Llc. if you feel you need any of these items inspected on your vehicle, because a quick look can sure save a lot of pain down the road.

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Posted in the Exhaust