Readers code and scanning tools interact with the on-board computer or vehicle diagnostic system to identify or troubleshoot problems. The code reader is a simplified version of the scan tool, but it is only capable of performing a basic scan for trouble codes. The scan tool can read and clear trouble codes, and can also provide advanced data reading and playback functions, knowledge bases, diagnostic procedures, and built-in testing equipment.
Read, display and clear vehicle trouble codes.
Reset check engine light.
More advanced or expensive code readers can read and display data, reset readiness monitors, or access parameter identifiers (PIDs) provided by the onboard computer.
Read the pending, generic, and manufacturer-specific codes.
Provide troubleshooting information, tips, and trouble code definitions.
Record and play back live data.
Plot data or access to specific parameter identifiers (PIDs).
More advanced scanning tools include diagnostic equipment such as scopes and multimeters.
Because these devices cheap and easy to use code readers are convenient for car owners and mechanics who want to read and clear diagnostic codes. Scan tools are more expensive, but can do everything a code reader can do, as well as provide troubleshooting tips, data readouts, and diagnostic hardware.
Automotive professionals typically need high quality scanning tools to work efficiently, while the average professional needs to be able to get by with cheap code reader or the nearest service willing to read the codes for free.
If budget is your priority, take your codes to an auto parts store or store. Many check and clear codes for free.
Code Readers Pros and Cons
The wide price range provides a wide range of features and options.
Very affordable — many are available for around $20.
Not as advanced, accurate, or useful as scanning tools.
Most people can get by with a free code reading service offered by their local parts store or by searching the internet to find out what the trouble code means.
No two code readers are the same. While feature sets are highly price dependent, any code reader can perform the basic task of reading, displaying, clearing codes, and resetting the check engine light in a vehicle.
More advanced code readers can do the following:
- Show fault code names.
- Read and display live data.
- Display freeze frame data.
- Show readiness monitor status.
- Reset monitor readiness.
- Provide basic access to the full range of parameter identifiers (PIDs) provided by the vehicle’s on-board computer.
Scanning tools Pros and cons
Sophisticated diagnostic and troubleshooting tool.
Some include advanced data reading and playback features, knowledge bases, diagnostic instructions, and built-in test equipment.
Very expensive — some cost several thousand dollars.
Steep learning curve.
Spending a lot of money on a consumer-grade scanner only makes sense if you’re a car enthusiast or DIY hobbyist with a small fleet of vehicles, not to mention a big budget.
Scanning tools usually offer a range of features depending on the budget and intended use. Low-level consumer-grade scanning tools provide code definitions and basic troubleshooting tips. High-quality scan tools include more detailed diagnostic and troubleshooting procedures, and some have built-in test equipment such as scopes and multimeters.
Here are a few things a scanning tool can do: