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How to Use an OBD2 Scanner

OBD2 Car Code Reader

Today’s vehicles are often referred to as computers on wheels, and that’s fair. The advanced technology that’s built into them can provide warnings about potential issues automatically. Cars employ sensors that monitor the fuel, ignition, transmission, and emissions systems – and often more – and they alert the driver when an issue has been detected.

What Is OBD2?

An OBD2 port is a universal interface in cars, typically found just underneath the steering column. Anyone can connect a computer to an OBD2 port – using a special cable – and read and analyze data about the car. That helps mechanics and others repair a vehicle and return it to service. Consumers can also buy OBD2 scanners and diagnose problems themselves.

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OBD1 vs OBD2

Vehicle monitoring systems – known as On-Board Diagnostics (OBD) – have grown more elaborate and sophisticated over the years. Introduced in the early 1980s, the first OBD readers were vehicle- or manufacturer-specific and provided limited data. They could only be accessed by using proprietary, and often expensive, equipment. The only readily available consumer-level information was in the form of an icon on the gauge cluster, often referred to as an “idiot light.”

Starting with the 1996 model year, the EPA mandated that all vehicles had to have a universal On-Board Diagnostics II (OBD-II or OBD2) port installed. The single standard led to the development of affordable consumer OBD2 scan tools; a bare-bones code reader can be had for under $50, and it’s likely to meet the average consumer’s needs.

Things have even advanced beyond that. Cars today may include systems that can alert you of OBD codes automatically, and help you contact your dealer to order parts.

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OBD2 Scanner Plugged Into OBD2 Port

OBD2 Scanner Plugged Into OBD2 Port / Photo Credit: Carfax

How to Connect and Read an OBD2 Car Code Reader

  1. Using an OBD2 car diagnostic scanner is simple and straightforward. Before you get started, get familiar with the scan tool’s user manual and documentation.
  2. Plug the standard OBD2 connector into the vehicle’s port located under the driver’s side of the dashboard.
  3. Turn on the car to power the scan tool or code reader.
  4. If necessary, enter any vehicle-specific information requested. Many tools will ask for the Vehicle Identification Number (VIN).
  5. To check for engine codes, press the “scan” button on the code reader, and follow the directions on the screen.
  6. A scan normally takes just a few seconds. Once it’s complete, follow the screen prompts to see if the vehicle is reporting any trouble or error codes. Record the data.
  7. If you’ve used the data to fix the vehicle or simply want to see if the code was a one-time issue, use the scan tool to clear the reported codes. This will reset the check engine light.

I Have the Diagnostic Trouble Codes (DTC) – What Now?

Once you have the trouble code, an internet search can help you diagnose repairs. Better yet, many of the more sophisticated scan tools will provide you with both the trouble code and the code description right on the scan tool’s screen. Some will even use vehicle-specific information to report which parts need to be replaced or fixed to remedy the problem.

It’s a particularly useful tool if your car’s check engine light has been illuminated. You can look at the check engine light code to discover if it’s a serious problem (like something that would cause you to fail an emissions test), or just a reminder to change the car’s oil, triggered by the car’s mileage.

Once you’ve established what the code means for your particular vehicle, you can use the information to purchase parts so you can repair the car yourself, or you can share the data with your mechanic. Even if your mechanic runs the codes and does independent diagnostic work, you can use the information you’ve gathered to confirm the mechanic’s assessment.

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Different Types of OBD2 Diagnostic Tools and Their Prices

There are hundreds of OBD2 diagnostic code readers available, and they cost anywhere from $50 to $3,000. Be careful which one you choose; you could easily purchase an automotive scan tool that reads only a small amount of your vehicle’s available information.

With up to five different communication systems used in OBD2-equipped vehicles, it is important to contact your vehicle’s manufacturer or consult another reliable source to discover which OBD2 system your automobile supports.

Because very few people keep the same car forever, it can be wise to buy a tool that can be used on more than one vehicle and upgraded in the future. If you find your current ride requires just an inexpensive basic scan tool, you might want to buy a relatively cheap unit. On the other hand, if you are making a costly purchase to cover all of your vehicle’s systems, the ability to upgrade will enhance the scan tool’s value.

Many automotive shops and dealers have large, computer-based machines that allow two-way communication between the scan tool and the vehicle. While the dealer’s pricey super-scanner is unnecessary for a home mechanic, the smaller handheld units can be very useful.

Bluetooth Wireless OBD2 Scanner

Bluetooth Wireless OBD2 Scanner / Photo Credit: Carfax

App-Based Wireless OBD2 Scanners

Some tools require you to plug the device into a computer to read the diagnostic information. However, newer wireless Bluetooth OBD2 code readers work with a smartphone or tablet. These new tools change the OBD2 rules, making complex code scanning and real-time vehicle information readily available, even for those on a shoestring budget.

A small Bluetooth-enabled harness plugs into an OBD2 port and syncs up to your phone in a matter of seconds. It’ll give you the status of currently running systems, and more. The system also stores codes on the phone or tablet and keeps extensive logs.

OBD2 Scanners Are for Everyone

Whether it’s handheld, wireless, or built into your vehicle, an OBD2 reader is a great way to diagnose many vehicle repairs inexpensively and easily.

Remember to research before you buy, and seek counsel before purchasing parts based on a trouble code.

Even if you never plan to lift a wrench, owning a car scan tool empowers you to be a part of repair decisions by arming you with vital information.

If you have questions about this story, please contact us at Editors@carfax.com