What’s the Deal With Vehicle Diagnostics?
Your car is making a strange noise.
You are experiencing a vibration at high speeds.
Maybe the check engine light is on.
Why is this happening? Chances are, you will need professional automotive diagnostics performed at a trusted auto repair shop.
What Are Automotive Diagnostics?
Automotive diagnostics are the process of using tools, technology, testing procedures, road tests, and physical inspections, combined with years of experience, to determine the cause of vehicle problems.
Diagnostics are performed to determine the cause of mechanical, electrical, and software-related issues so mechanics can properly advise on repair paths to fix a given problem. They are the foundation of accurate and cost-effective repairs.
What is Required to Perform Proper Auto Diagnostics?
Trained mechanics
Proper diagnostics require skilled and experienced mechanics to not only understand a vehicle's mechanical and electrical systems but also interpret codes and symptoms, perform research, and consult past experience.
Technology and tools
Diagnostics require specialized equipment for various uses, including to
- Read trouble codes
- Evacuate air conditioning systems
- Run pressure tests
- Perform smoke machine tests
- Check voltage and resistance
Time
Diagnostics require mechanics’ time to:
- Perform physical inspections
- Go on test drives
- Put the vehicle on a lift
- Recreate intermittent issues customers are experiencing
- Perform research based on the specific year, make and model of the vehicle
Why are Auto Diagnostics Important?
When you invest in repairs, you should invest in repairs that will fix the issues you are experiencing in the most efficient manner. For drivers in Chatham, NJ, proper auto diagnostics are important because they determine the repairs that you should spend time and money on to fix your automotive issues.
Correct diagnostics ultimately save you money; you get the correct answer as soon as possible, so you pay for what you really need to get done. It eliminates guesswork.
Proper diagnostics also save you time; getting correct answers the first time around allows you to limit the time your vehicle is in the shop.
With that, it is always important to remember that some problems require a step-by-step repair process. Sometimes, “Step A” must be completed before determining whether “Step B” is necessary. Even in these cases, proper diagnostics ensure you’re on the most efficient path to a solution.
Are Automotive Diagnostics Ever Free?
Customers often expect automotive diagnostic fees to be put toward the final repair bill if they choose to get repairs at the shop that diagnosed their issue. There are a few important factors to consider:
The Skill Factor
Auto diagnostics are oftentimes the most challenging part of the auto repair process. Interpreting codes, performing electrical tests, and reading wiring schematics are not easy. Auto diagnostics are a critical skill that differentiate an average shop from a great shop.
The Business Reality
It’s expensive to hire trained mechanics and to purchase reliable equipment. If a shop is giving diagnostics for free, it is likely that the customer won’t get much out of the service, or that the diagnostic cost will be factored into the repair job, perhaps with a higher labor charge.
You have to ask yourself: “Am I really getting anything for free?”
Some automotive issues are much more obvious than others. Maybe you hear a grinding noise when braking. If a quick visual inspection of your brake pads shows that they need replacement, a diagnostic fee may or may not be charged, depending on the shop.
Electronic Automotive Diagnostics
“Why am I paying so much for you to plug a scanner into my car?”
This is a common misconception in the automotive industry. Yes, the first step to understanding a check engine light is using a scan tool to understand what type of code is displaying on your vehicle.
However, the code does not provide an obvious repair path to the mechanic every time. Take this situation for example:
Catalytic Converter Code
A catalytic converter code doesn’t necessarily mean it needs to be replaced. A sensor may be bad, causing the catalytic converter to not perform properly and affect the performance.
In the case of a bad sensor, if a mechanic suggests just changing the catalytic converter based on this code, the problem will return until the sensor issue is taken care of. (And you’re out hundreds or thousands of dollars that wasn’t necessary).
This is a great example of why customers need proper start up diagnostics and sometimes additional specific diagnostics to locate their automotive problems. Sometimes, the actual problem sets false codes, so problems need to be categorized into two groups: problems that need to be addressed and problems that will not return after the proper repair has been completed.
Here are some more examples of why electrical diagnostics is more than just plugging in a scanner:
Misfire code
You have a check engine light, and you scan it yourself. It’s a misfire code. You might think you need to change a spark plug. There’s a possibility that a spark plug does need replacing, but it could also be:
- an ignition coil
- a fuel injector
- a valve problem inside the cylinder
- a wiring problem to the ignition or fuel system
- an issue with the ECM (Electronic control module)
Diagnostics at an experienced shop would help determine which one of those problems is actually causing the code.
EVAP code
Let’s say you have a check engine light for an EVAP code signaling an issue with the emissions system. The next step is not straightforward because of the nature of the possibilities with an EVAP code. After initial diagnostic testing, smoke testing might be required to identify leaks.
Common EVAP problems include
- a gas cap problem
- a purge valve for the tank
- a vent valve for the tank
- a rotted or broken tubing for the EVAP system
- a wiring problem
Without proper diagnostics, EVAP problems can be misdiagnosed repeatedly.
Final Thoughts on Automotive Diagnostics
There is a common misconception about automotive diagnostics. It’s common for customers to question diagnostic fees, as many don’t expect to pay for the time spent identifying the problem. However, in many industries, including medical and legal fields, it is expected to pay for professional evaluations, diagnoses or legal consultations. Automotive diagnostics follow the same principle, now more than ever with the constantly evolving electrical components in modern vehicles.
When in doubt, ask your local mechanic in Chatham, NJ to walk you through the diagnostics they are suggesting. This helps to understand how mechanics will be identifying and solving your car’s problems.