Q: Are Code Readers and Scan Tools Different?

asked by on

Are code readers and scan tools different?

There are differences and similarities between code readers and scan tools. With the advent of the vehicle on board diagnostic system (OBD) there have been many different makers of scan tools and code readers. The code readers were the first to be made once the manufacturers allowed the information to be retrieved for a mechanic to access it.

Before there were code readers and scanners (scan tools), the mechanic would have to put the system into test mode and count a blinking light or a meter needle sweep to obtain a code, then hook up a tool called a breakout box. This box was installed between the vehicle computer and its wire harness. The mechanic would have to test each computer input and output using a multimeter to get the readings of sensors. This was very time consuming and not a convenient way to find a problem. Later, large vehicle scanners were made that could not leave a mechanic bay due to size. Then they started getting smaller and smaller. They still had very limited diagnostic use for a trained mechanic, but were needed for extended diagnostics.

Then the code reader was created. The code reader was about the size of a small book and would hook up to a diagnostic connector that was specific to one manufacturer only. The code reader would be used to test the vehicle engine only and get trouble codes output to a small screen. The code was used by a mechanic to do a pinpoint test using other tools before they repaired and retested the system to see if the code was gone. There was no other use except to retrieve the codes and no other information was given. With the advent of the OBD II system in 1996, the code reader got a generic connector that is used by all manufacturers. The code reader can still retrieve codes and clear codes.

With the OBD II system, manufacturers got more information that is given through the OBD connector. To access this information, a scan tool (scanner) can be used. A scanner can be very simple and only get basic information like engine codes and engine emission monitors, and also be able to clear codes. The scanner can also get very comprehensive with the ability to see live data input and outputs of the computer, access other systems data and codes like the anti-lock brakes, suspension, powertrain, body control, and air condition system. The scan tools today can even have reprogramming capabilities using manufacturer’s calibration files. However, not all scanners are the same as the more expensive ones have more functions. The manufacturers’ dealers will have scanners that have proprietary information that most aftermarket scanners have access to. This is so the dealer can have access to information like manufacturer specific codes and data, anti-theft systems, or other systems the manufacturer does not want the general public to have access too.

The bottom line is code readers can only retrieve codes and clear them, while scan tools can also test other systems and data usage to help diagnose problems better than just a code reader.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Are Code Readers and Scan Tools Different?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: ABS light error codes

Hello. The ABS fuse will be located in the central junction box inside of the engine bay of your 2005 Ford E-250. It is likely that you have a short somewhere that is causing fuses to blow or interrupting another...

Q: Loss of power under acceleration

Hello, thank you for writing in. The components you have checked thus far have been valid steps. You want to go through system by system, and make sure the engine is getting what it needs. Start with the fuel system,...

Q: Engine misfiring 2003 Honda CR-V

Misfires can be caused by several things. I would first check for vacuum leaks, then I would pull the plugs to see if they need replacing. It is possible that have a fuel system concern, but I would lean more...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...