Check Engine Light Diagnostics - Warning Lights

Check Engine Light Diagnosis

We're experts at check engine light diagnostics for your BMW, Mini, Subaru and Volvo vehicles. From misfire diagnosis, to drivetrain malfunction indicators and rough running concerns. There are so many ways we can save you money as opposed to going to a traditional shop, and our quality of work sets the standard.

There are a myriad of warning lights that may illuminate on your car. Leave it to North State Auto to properly diagnose and repair just about any warning lights your vehicle may display on the dashboard. Here are some of the common warning lights we diagnose and repair.

• Check Engine Light  
• Drivetrain Malfunction
• ABS / DSC / Chassis Stabilization
• Battery Warning Light
• Brake Warning Light
• Tire Pressure Warning Light

Is It Safe To Drive My Car With Warning Lights On?

Maybe. It depends on which warning light(s) are on and how your vehicle is running. Obviously if your engine starts running poorly or making awful noises, turn it off! You may be causing more damage. A check engine light that is flashing generally indicates an active misfire, however if it remains on without flashing, and your vehicle seems to be running okay, it's likely safe to drive minimally until you can get it looked at. Sometimes it's a failed sensor or unmetered air leak, other times an internal engine component like a timing chain may be out of tolerance. Some other warning lights that you should pay close attention to are engine oil pressure warnings and battery or charging system warnings. A charging system malfunction can be indicative of a failed alternator, battery, or serpentine belt. Any of these problems can leave you stranded. An engine oil pressure warning light can lead to catastrophic engine failure. An ABS or traction control system warning light may not make your car run poorly, however it reduces the vehicles ability to mitigate safety risks on the roadway. An airbag or SRS warning light also won't make your vehicle run poorly, but it can result in failures of certain passive restraint systems or airbag deployments in the event of a collision.

Auto Diagnostic Services

Why did my Check Engine Light Come on?

Your Check Engine Light or Drivetrain Malfunction Light may be on for any number of reasons. There are literally hundreds of possible error codes that may be stored in your DME (engine control unit) or other drivetrain control units. Often times, owners believe that all they need to diagnose their vehicle is to get the free code scan at the auto parts store, and the code will tell them exactly what to replace. While this may work once in a while, retrieving the fault codes from the ECU is merely the first step in the diagnostic process.

The example outlined below happens every day to European car owners who are trying to save money, but end up paying a lot more in the long run, while throwing low quality parts at their problem.

Example: Tom's check engine light comes on and his engine is running poorly, he goes to get the free fault scan from the auto parts store. They tell him the code stored is p0170 for fuel trim malfunction. This code is generally set when the fuel mixture is too far out of range, referring to the air/fuel ratio. There's also misfire codes stored. The 20 year old parts guy who doesn't work on cars says "it's probably your air mass meter, and the misfires mean you need new spark plugs. Oh, look, we have all those parts, that'll be $364.79."

Tom buys the parts and installs them. His problem persists. he goes back to the parts store. The kid says, "oh, you probably also need a fuel filter and oxygen sensors." Another $3-400 later, Tom decides he doesn't want to crawl around under his car to replace those other parts. He takes his car to a shop and requests them to be installed. Shop owner suggests properly diagnosing the vehicle, to which Tom replies "it's already diagnosed, just replace these parts please." He pays $200 in labor for those parts to be replaced.

Now he's thrown almost $1000 in parts and labor into this problem, and guess what, it's still not fixed. Out of frustration Tom calls us at North State Auto. We perform a smoke test to check for intake or PCV leaks, and find his intercooler charge pipe is split wide open. It's causing the air/fuel ratio to be so far out of range, it's causing misfires. Tom pays us $289 for diagnosis and repair. Now his car runs fine.

The moral of the story is, a code scanner doesn't tell you what the problem is, it just leads you to it. You still have to diagnose the root cause of the code. Would you rather pay roughly $300 for a diagnosis and repair, or throw random parts at your car in  excess of $1000 over the course of a week or two, only to accomplish nothing?

This is just one example out of hundreds of possible scenarios. We can't fix every car for $300. Sometimes, a car needs extensive work, sometimes we can fix it in 20 minutes and charge very little. The point is, we are experts on these cars, we know what to look for, and have the equipment to test nearly anything.

Auto parts stores are in the business of selling parts, not diagnosing cars. Would you take your Keurig Coffee machine to Starbucks and ask them why it doesn't work? Would you go to the drug store if you're experiencing major chest pain? No, that would be dumb. However the auto parts stores have people convinced that they know how to diagnose cars. They do it for free to escape liability from a legal standpoint. They just sell parts, and their free "diagnosis" is an easy way for them to do that.