Complete Guide to OBD Diagnostic Tools: How to Choose and Use Your Car Scanner to its Best

OBD2 scanners are devices that connect to the vehicle's ECU via the diagnostic port to communicate with it and find problems. While there are many different features depending on the make and model, the basic function of any OBD2 scanner is to read engine trouble codes. For example, when your check engine light comes on, an OBD2 scanner can give you a general description of the problem, providing a starting point for diagnosis.

What does an OBD2 scanner do?

At a minimum, an OBD2 scanner should be able to read and clear diagnostic trouble codes (DTCs). Even if you are not a professional mechanic, having an OBD2 scanner can be useful for several reasons:

- Maintaining your vehicles

- Checking emissions before MOT

- Confirming the mileage of a used car before purchasing

- Reading error codes to understand why a certain light has come on

In addition to these basic functions, some tools offer advanced features that can vary greatly:

- Calibrating the steering angle sensor (SAS): Important for the correct functioning of the steering system. The sensor must be recalibrated after a wheel alignment.

- Resetting the diesel particulate filter (DPF): Essential to prevent the filter from clogging and ensure the correct functioning of the diesel engine.

- Adaptations and coding: Allows you to synchronize new components with the vehicle's control units after a replacement. Allows you to do retrofits for certain car brands.

- Real-time monitoring and graphs: View real-time data such as engine temperature, RPM, and other information that can help you optimize performance.

- Freeze frame data: Records information about the vehicle's systems at the time a fault was logged, which is useful for accurate diagnosis.

These advanced features are especially useful for those with basic mechanical knowledge. For non-mechanics, the most useful features are still reading fault codes and emissions testing.

Is an OBD2 scanner worth it?

If you're just looking to make simple repairs or make sure your car passes emissions testing, a basic OBD2 scanner can be a great investment. It's useful if you want to verify a diagnosis made by a mechanic or find out why your check engine light came on. For more advanced tasks, such as reprogramming the engine control module (ECM) or changing vehicle settings, you'll need a specialized scanner. These advanced tools are also useful if you regularly work on multiple vehicles or want to monitor real-time data such as ABS sensor or misfire information.

If you frequently work with different vehicles or want a scanner that is compatible with both domestic and foreign cars, it may be worthwhile to go for a more advanced model with regular updates. However, keep in mind that more features and programming options mean a higher price.

OBD2 Scanner Compatibility

While many OBD2 codes are universal, there are a number of brand-specific codes that not all scanners can read. If you own a vehicle built before 1996 or a less common model, it is a good idea to do some research to see which OBD2 scanners are compatible with your vehicle.

In addition to universal codes, each car also has manufacturer-specific fault codes. While most OBD2 scanners can read most fault codes, this is not always the case. Many mechanics point out that some specific codes cannot be read by every scan tool. If you plan to use your OBD2 scanner on a specific vehicle or range of vehicles, make sure the tool can read fault codes from that manufacturer.

OBD2 Protocols

Not all ECUs use the same "protocol" to communicate with the OBD2 scanner. Here are the 5 most common OBDII protocols:

- ISO 15765 (CAN bus): The most common protocol, used in vehicles produced in the United States from 2008 onwards.

- ISO 14230-4 (KWP2000): Common in vehicles produced in Asia from 2003 onwards.

- ISO 9141-2: Common in vehicles produced in the European Union and Asia, as well as Chrysler vehicles between 2000 and 2004.

- SAE J1850 (VPW): Common in older GM vehicles.

- SAE J1850 (PWM): Common in older Ford vehicles.

How to Use an OBD2 Scanner

Although each OBD2 scanner has different buttons and interfaces, the process of using it is generally very simple:

1. Plug in the scanner: Find the OBD2 port under the steering wheel, on the left. The connector is trapezoidal in shape and contains 16 pins.

2. Turn on the ignition or engine: To read the error codes, the instrument cluster must be turned on.

3. Read the codes: Whenever your car's computer detects a problem, it will record a Diagnostic Trouble Code (DTC). Codes start with a letter that indicates which part of your car is having a problem:

- P: Powertrain problems (engine, transmission, fuel system)

- B: Body issues (steering system, airbags, seat belts)

- C: Chassis issues (axles, ABS, wheels)

- U: Communication issues (possible wiring problem)

Some DTCs are generic, while others are manufacturer-specific. You can search for these codes online to better understand the source of the problem. OBD2 scanners can also erase the codes from your car's computer. If the problem is not resolved, the code and light will come back on.

Differences between OBD1 and OBD2

- OBD1: Introduced in the 80s, each manufacturer had a different protocol, making it less universal, so there are different adapters on the market that we also find supplied with some professional diagnostics.

- OBD2: Standardized since the mid-90s, used on all vehicles produced after 1999 in Europe. It is compatible with all multi-brand scan tools.

Why choose a professional scan tool?

A professional tool offers several advantages over a simple scanner:

1. Advanced diagnostics: Full access to all vehicle modules for more precise diagnosis.

2. Comprehensive functionality: Ability to perform complex tests such as coding and programming.

3. Regular updates: Ensure that the tool stays up to date with technological innovations.

4. Remote support: Possibility to receive direct assistance via remote connection of the device.

One of our most popular professional tools is the Autel MaxiSys, equipped with the topological mapping system to view all the vehicle systems.

Conclusion

Choosing the right OBD2 scan tool can make all the difference in vehicle maintenance and repair. With the right knowledge and the right tools, you can save time and money, and keep your car or shop running at peak efficiency.

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