What Does a Car Diagnostic Tell You? Answered

August 4, 2022 Steve Jones

Last updated on July 19th, 2024 at 02:52 am

All modern cars have computers inside, and diagnosing problems in order to fix the car is completely different than it was in the past when everything was pure mechanics. In order to communicate with ECU (electronic control unit), you will need a car diagnostic tool. But, what do car diagnostics tell you? In this article, I’ll guide you through what car diagnostics can help you with.

Of course, not all car diagnostic tools are the same, and not all of them are good enough to do a thorough vehicle check and fix some issues. And even though most cars have the same OBDII ports, they can’t all be checked with the same diagnostic tools, which I’ll talk about later.

If your car has an OBDII port (if it’s newer than 2000, it probably has), this article might be interesting to you, so make sure to read the whole article.

What Can Car Diagnostic Tools Tell You?

Let’s look at some of the most important things car diagnostic tools can tell you about your car.

Car diagnostic tools can check data about:

Engine
ABS brakes
Ignition system
Steering wheel
Airbags
CANbus
Instruments (dashboard, etc.)
Air conditioning system
Infotainment system
Check all kinds of sensors
Turbo
Car equipment
Car details (VIN number, serial numbers of parts, etc.)
With some tools, you can even check the mileage

So, as you can see, car scan tools can check almost everything since most car parts are connected to various ECUs. Modern cars usually have more than 50 electric control units.

Car diagnostic tools can tell you various data for the control modules mentioned above. That data includes:

Readings of data
Measurements of pressure, speed, injectors, etc.
Adaptation and programming (e.g., removing seat belt warning)
Service intervals (reset, change, DPF and EGR regeneration, etc.)
Reading fault codes
Clearing fault codes

Long story short, car diagnostic tools can tell you the most important things about your vehicle’s health. If there are some issues with your cars, car scan tools will probably show it. Of course, they’ll only tell you the issue occurs on some car parts that are connected to ECUs.

A few days ago, my friend asked me to remove the seatbelt warning on his VW Golf MK7. It took me 2 minutes to complete the task. And even better, I also enabled the needle sweep option on his cluster, and he was amazed by that.

Having a diagnostic tool is also essential for most car detailers out there. Sometimes, after removing the front car seats, the airbag light may show on the cluster. By using a scan tool, it’s a 2 minutes job to delete the error code.

Are All Car Scan Tools The Same?

You may think that all car scan tools can do the same things. However, it’s not like that. Some brands require specific diagnostic tools in order to show you all the data.

There are plenty of cheap diagnostic tools on the market, and they’ll work with most brands, but they’ll show you only the most basic data, such as engine codes, etc. But you won’t be able to make any adaptations, clear safety codes (Airbags), and many more.

While I don’t have anything against cheap obd2 scan tools (they’re quite useful sometimes), they’re nowhere near more expensive tools that give you access to all the ECUs in the car. I had a few cheap scan tools, and they were good for showing some basic errors and data, but nothing more.

Since I got a professional car diagnostic tool, I’m able to play with all the ECUs in my car, which is fantastic. Also, I was able to diagnose some problems and prevent further damage to my and my friends’ vehicles. Without professional tools, I wouldn’t be able to do that.

Can You Get a Universal Diagnostic Tool?

Well, in the last few years, more and more diagnostic tools have been appearing on the market. And honestly, some of them are quite good. Making a universal car diagnostic tool is often expensive because it should cover thousands and thousands of codes from various brands. And even then, they may not be able to read and change all the data on ECUs. Sometimes, they may even show you completely wrong data.

In my opinion, the best universal diagnostic tool that you can get is Carly. It fits most car brands and is quite good at diagnosing problems and adapting car ECUs, as well as checking some other data.

However, if you’re extremely serious about using the best car diagnostic tool, you’ll then buy a brand-specific scan tool that’s made for a few brands only. That way, they can pay all the attention to one brand that mostly uses similar ECUs, and by doing that, all potential bugs are minimal.

I mentioned it earlier. I wasn’t able to check all the data literally until I bought a specific diagnostic tool for VW cars, which is called VCDS by Ross-Tech. So, if you want complete control of your vehicle, you should look for specific diagnostic tools made for your vehicle.

Best Diagnostic Tools For Specific Car Brands

Here’s a quick table that I made where I’ll show you which diagnostic tools are best for specific brands so that you know what to look for based on what car you own. Of course, I won’t mention all car brands, just some of the most common ones

Car Brand	My Recommended Diagnostic Tool
VW, Audi, Seat, Škoda	VCDS by Ross-Tech
Porsche	Piwis 2
Toyota, Honda, Nissan, Mazda, Subaru, Acura	ANCEL JP700
Ford, Lincoln, Mercury	IDS (Integrated Diagnostic System)
Chevrolet, GM, Cadillac, Buick, Hummer	Vident iLink400 GM
Mercedes-Benz	iCarsoft MB 2
BMW	Ista D & Ista P
Fiat, Lancia, Alfa Romeo, Jeep, Suzuki	MultiECUscan
Chrysler, Dodge, RAM	Appcar DiagFCA
Lincoln	ForSCAN
Tesla	Tsla PRO Scanner
Mitsubishi	iCarsoft JP
Land Rover, Jaguar	Autel MaxiCOM MK808

Final Words

For whatever purpose you want to use car diagnostic tools, you should know their capabilities and options. That’s why it’s always important to check all the data before you make a purchase. High-quality car scan tools are a perfect addition for every car lover, especially for DIYers who like to do some stuff by themselves.

So, to conclude, car diagnostic tools (high-quality ones) will tell you all the details of your vehicle so that you can get a better picture of the overall condition of the car, that you can resolve any issues quicker, and most important – for a lower price since you won’t be paying mechanics every time they scan your vehicle.