Last updated on April 16th, 2021 at 02:20 pm

You are a do-it-yourself guru when it comes to installing and repairing car stereo systems, but how about when it comes to the mechanics? When you have a simple issue, do you really need to take the vehicle to the mechanic for expensive diagnostics, or can you figure it out yourself? Thankfully, the innovative tools available today don’t require you to be an ASE Certified Master Tech to know what’s wrong with your vehicle. You can use an OBDII scanner and find out precisely what is wrong.

Let’s look at the tool you need to diagnose common automobile problems and take a quick glimpse into how to use this equipment.

What is OBDII? A Quick Background

On every vehicle sold in the United States since 1996, there is a connector to the OBD-II system. Prior to that, the system was OBD-I instead.

OBD2 stands for on-board diagnostics, version 2, and it helps you identify what is wrong by looking at codes given to the computer. When your car’s on-board computer detects a malfunction, it sends out a code, which can be read by the best OBD2 scanner models.

These codes show you the malfunctions with the powertrain, emissions system and other parts of your vehicle.

Getting Your Hands on an OBDII Scanner

You don't have to buy a scanner to find out what's wrong with your vehicle. You can run down to the auto parts store every time your Check Engine Light comes on and have them do a free scan of your system. But who wants to do that when you can buy your own OBD-II scanner at a reasonable price?

Most scanners provide the code along with a description or meaning. Some models, such as the BlueDriver OBDII scanner, take this a step further. With this setup, you can see what the most common fixes are for your problem, get access to a list of parts you might need and see the average costs.

With this capability, you can save a lot of money.

OBDII Modes of Operation

As you explore the various OBD2 scanner options, you will notice ten modes of operation. Keep in mind that vehicle manufacturers are not required to support all ten modes. For most people, modes 1 through 4 are all you will need. Here’s the breakdown of these four modes.

  • Mode 1: Show data parameter IDs. These parameter IDs, otherwise known as PIDs, are the live sensor data that you will see in real-time.
  • Mode 2: Show freeze frame data. With this data, you get a snapshot of the car’s PIDs at the exact time when the trouble code was initially logged. Just keep in mind that the data was recorded for a few seconds, so there might be some data that is unrelated to the event.
  • Mode 3: Show stored DTCs. With this mode, you get to see all of the codes currently stored in the vehicle’s computer. Often, these codes start with the letter P and then are followed by four various numbers (more about that in a moment).
  • Mode 4: Clear DTCs. Once you receive the trouble codes and know what you are looking at, you can erase them.

The remaining modes are for advanced diagnostics and generally aren’t used by the everyday home mechanic.

Connecting the OBDII Scanner

When you pick the scanner for your needs, you want to figure out how much information is necessary. Then, you retrieve that data by connecting your code reader or scan tool to the car’s diagnostic port. You will find this 16-pin connector under the driver’s side of the dash, in most vehicles.

Then, follow these steps.

  1. Turn on the vehicle ignition.
  2. Power up your scanner if it doesn’t turn on automatically.
  3. Follow the instructions with your scanner to read the data.

If you have multiple codes showing up, you might need to scroll through them or press a particular button to move on. Make sure you write down anything that you see. Don’t ever erase the codes until you have resolved your issues.

What Do the OBDII Codes Mean?

You have the codes, now what do you do? You can search the OBDII codes with a troubleshooting guide online to get some ideas of what is going on. Here’s the breakdown of what each character of the code means.

First Letter: Most of the codes begin with a P. This means “powertrain.” If you have a professional scanner, you might also get codes for the body (B), chassis (C) and communications (U).

First Number: This number indicates if the problem is generic. Most generic codes are going to start with P0 or P2.

Second Number: This digit tells you what system is causing your issue. A 0 or 1 indicates trouble with the fuel or air metering system. It could be related to a bad oxygen sensor, as one example. 2 is a problem with the fuel or air metering injection system, such as the fuel injectors. With a 3, you are looking at ignition-related parts. A 4 would indicate the emissions system, while a 5 shows trouble with the idle control or vehicle speed controls. Sometimes air conditioning issues can trigger this as well. With a 6, you want to look at the computer output circuit, while the 7,8 and 9 discuss transmission issues.

Last Two Numbers: These two numbers show you the specific issue. Again, it won’t give you all of the answers but will lead you in the right direction. For example, if a code indicates that the engine is misfiring, it might be caused by several malfunctions.

Use an OBDII Scanner and Save Money

Sure, you have to pay a little money up front to get a reliable code scanner, but in the long run, it pays for itself. The last thing you want is to take your vehicle (filled with expensive car audio equipment) to some shady mechanic. It would be far better if you could repair the problem yourself.

We recommend doing your own diagnostics when your Check Engine Light comes on. Not only will you feel a sense of pride when you troubleshoot the issue, but you can save money that can later be used toward more audio equipment. It’s a win-win situation.