The check engine light has an unfortunate talent for coming on when everything seems perfectly normal.

The car starts. It drives. Nothing sounds terrible.

So do you keep driving? Bring it in immediately? Buy a code reader? Ignore it and hope it goes away?

The answer depends on what the vehicle is doing.

What the Light Actually Tells Us

Your vehicle’s computer monitors numerous systems while you drive. When it detects certain faults, it stores diagnostic information and may turn on the check engine light.

Here’s the part we wish more drivers understood: reading the code isn’t necessarily the same thing as diagnosing the car.

The code tells us what the computer noticed. Our job is figuring out why it noticed it.

Sometimes the path from code to repair is straightforward. Other times the component mentioned in a trouble-code description isn’t the component that failed at all.

That’s why we test before we start replacing parts.

A Steady Light and a Flashing Light Aren’t the Same Thing

If the check engine light comes on steadily and the vehicle is otherwise running normally, don’t panic.

It does need attention, but it doesn’t automatically mean the engine is about to quit. Pay attention to how the car is behaving and arrange to have the problem checked.

A flashing check engine light is different.

A flashing light can accompany a severe misfire or another condition that can cause additional damage. If the engine is shaking, losing substantial power or running very poorly, continuing to drive it can make matters worse.

That’s when we’d rather have you call and ask before deciding to keep driving.

“The Parts Store Told Me It Needs an Oxygen Sensor”

Maybe it does. But we’d still want to know why.

Suppose the computer reports a condition involving an oxygen sensor. The sensor could be bad. It could also be correctly reporting a problem caused somewhere else.

If we replace a perfectly good sensor without finding the underlying problem, we’ve spent the customer’s money and still have the same car to diagnose.

That’s not much of a repair.

Tell Us What Happened

Good diagnosis starts with information.

If you can, tell us what was happening when the light appeared. Was the engine cold? Were you accelerating? Did it happen after getting fuel? Is the car idling differently? Did fuel economy suddenly change? Does it happen only in the morning?

Those details can matter.

You drive the vehicle every day. You know what normal feels like. Something that seems insignificant to you may be useful information to us.

Don’t Erase the Evidence

If possible, don’t clear the codes immediately before bringing the vehicle in.

Diagnostic information stored by the computer can help us determine what happened. Clearing everything can remove useful information and reset monitors.

And if the light goes off by itself, don’t assume you’re imagining things. Some problems are intermittent. Tell us that too.

Why We Diagnose Before Replacing Parts

Modern cars can have several systems interacting with one another.

One underlying fault can sometimes cause multiple trouble codes. The reverse is also possible: a seemingly simple symptom may take testing to isolate.

Diagnosis costs less than repeatedly buying the wrong parts.

When your check engine light comes on, we’re not interested in guessing which component might make the light disappear. We’re interested in finding the reason it came on.

If you’re in Marietta, East Cobb, Woodstock or the surrounding area and your check engine light has something to say, Automotive Services can help figure out what it’s telling you. Call us at (770) 928-6126.

Related reading: Services • Contact Us • Blog 9: Car Noises • Blog 11: Overheating

There are plenty of places around Marietta where you can have a car repaired. Finding somebody you trust to tell you what the car actually needs is a different matter.

We understand why people are cautious.

Most customers aren’t automotive technicians. When a mechanic says a vehicle needs a small repair or a major one, the customer has to put a certain amount of trust in the person standing on the other side of the counter.

We think a shop has to earn that trust.

Automotive Services has been family-owned since Emory Patton and his father, Howard “HP” Patton, opened it in 2009. HP had an old-fashioned approach to business. He knew customers by name, sat and talked with people while they waited and treated the person walking through the door as more important than the transaction.

Cars have changed quite a bit since then. That part of the business hasn’t.

Diagnosis Comes Before Repair

One of the first things we look for when a vehicle comes into the shop is the cause of the problem—not simply the symptom.

There’s a difference.

A check-engine code, for example, doesn’t necessarily tell a technician which part to replace. It tells us what the vehicle’s computer detected. From there, we may need to test the system to determine why it happened.

The same applies to noises, vibrations, overheating problems and many other complaints.

Parts swapping can get expensive quickly. We’d rather understand the problem first.

You Should Know What You’re Paying Us to Do

Automotive repair can get technical, but the explanation shouldn’t have to be.

If we find something wrong, you should be able to ask what we found, why it matters and whether it needs attention now.

Sometimes the answer is, “This needs to be repaired.” Sometimes it’s, “Keep an eye on it.” And sometimes there are several things a vehicle needs and we can help the owner decide what should come first.

That’s especially important with an older vehicle.

If a car has 150,000 or 200,000 miles on it, finding some wear isn’t surprising. The useful question is what matters now, what’s coming later and whether putting additional money into the vehicle makes sense.

Experience Still Matters

Modern vehicles have computers, networks, sensors, cameras and increasingly sophisticated control systems. The tools have changed dramatically.

The fundamentals of diagnosis haven’t.

You observe the problem, understand how the system is supposed to work, test it and follow the evidence.

Emory Patton is an ASE Certified Senior Master Technician and has spent decades working in the automotive field. That experience matters because unusual problems don’t always fit neatly into a trouble-code description.

We’ve seen a lot of cars—and a lot of problems.

Look at the Customers Who Keep Coming Back

When you’re evaluating a repair shop, don’t just look at the number beside the stars in an online review. Read what people say.

We’re particularly proud when customers talk about bringing multiple family vehicles to us or continuing to bring us an older car year after year.

Long-term relationships tell you something.

A shop that has serviced the same vehicle for years also has an advantage: we know some of its history. We know what has already been done and can help the owner think ahead instead of treating every visit like we’re seeing the car for the first time.

Independent Shop or Dealership?

There are situations where going to a dealership makes sense. Warranty repairs and recalls are obvious examples.

Outside of those situations, many people prefer having an independent shop they know.

We’re not interested in telling somebody that every dealership is bad or that an independent mechanic is automatically better. Neither statement is true.

What matters is whether the people working on your vehicle are qualified, whether they’re diagnosing it correctly and whether you trust their recommendations.

What We Think You Should Expect

If you’re looking for an auto repair shop in Marietta, East Cobb or Woodstock, we’d suggest looking for a place where you can ask questions.

You should know what was found. You should know what you’re authorizing. And you should feel comfortable asking whether something needs to be done today or can wait.

That’s how we’d want to be treated if we were standing on your side of the counter.

If you’d like us to take a look at your vehicle, give Automotive Services a call at (770) 928-6126.

Related reading: Our Story • Testimonials • Services • Contact Us