Standard OBD2 (On-Board Diagnostics II) systems are incredibly useful for accessing basic vehicle information. However, they often only scratch the surface of the data your car’s computer systems are actually collecting. For enthusiasts and those wanting a deeper understanding of their vehicle’s performance, delving into vehicle-specific CAN (Controller Area Network) codes can unlock a wealth of extra data. This guide will explore how you can leverage a 2-inch gauge OBD2 reader and CAN codes to access this hidden information, going beyond the limitations of generic OBD2 PIDs (Parameter IDs).
For many vehicles, manufacturers implement proprietary CAN codes that provide access to parameters not available through the standard OBD2 protocol. Think of it as accessing a secret menu within your car’s data system. For example, in certain car models, these custom codes can reveal crucial data like oil temperature – vital for performance driving and monitoring engine health – or precise fuel remaining levels, offering more accuracy than the standard fuel gauge.
Finding these vehicle-specific CAN codes is the first hurdle. Luckily, resourceful communities and online resources have made this task significantly easier. Here’s where to start your search:
- Online Forums Dedicated to Your Vehicle: Vehicle-specific forums are goldmines of information. Enthusiasts often share their discoveries, and you’re likely to find threads dedicated to uncovering CAN codes for your make and model. Diesel truck communities, for instance, are particularly active in sharing custom PIDs.
- Torque App Forums: The Torque Pro Android app is a popular OBD2 tool, and its associated forums are a fantastic resource for finding custom PIDs. Users frequently post their findings and share configurations for various vehicles.
- Scangauge X-Gauge PID Library: Scangauge is a brand of vehicle gauges that supports custom X-Gauge commands, which are essentially vehicle-specific CAN codes. Their online library (http://www.scangauge.com/support/x-gauge-commands/) is a valuable repository of codes, even if you’re not using a Scangauge device. You might find codes applicable to your vehicle listed there.
- CAN Bus Sniffing (Advanced): If your online searches come up empty, you can take a more hands-on approach by performing CAN bus sniffing. This involves using specialized hardware and software to intercept and analyze the data traffic on your vehicle’s CAN bus to identify valuable data packets and their corresponding codes. There are numerous online guides, such as this Instructables resource (https://www.instructables.com/id/CAN-Bus-Sniffing-and-Broadcasting-with-Arduino/), that can walk you through this process if you’re comfortable with a more technical DIY approach.
Once you’ve unearthed the correct CAN codes for the data you want to monitor, the next step is to integrate them into your OBD2 setup. For users employing tools like ELM327 OBD2 adapters and platforms like Arduino, this often involves sending specific commands to initialize the connection with the correct CAN header and then querying for the desired PID.
For instance, in the example provided in the original article, accessing oil temperature and fuel remaining on a specific vehicle (BRZ/FRS/GT86) required sending a custom CAN header command:
runCommand("AT SH 7E0",data,20); //(FRS/gt86/brz specific CAN header)followed by a query for the oil temperature PID:
status=getBytes("21","01",values,1);This code snippet demonstrates how you might need to modify your OBD2 interface code to accommodate vehicle-specific protocols. Libraries like the David Irvine API can be helpful in this process.
Finally, interpreting the data returned from these CAN code queries can be the last piece of the puzzle. The responses are often strings of hexadecimal characters, and extracting the actual numerical data requires understanding the data structure and potentially some trial-and-error. Debugging might involve sending the raw data to a serial monitor (an Arduino Mega can be beneficial for handling large data streams) and then analyzing it in a spreadsheet to identify which hex values correspond to the sensor readings you are interested in. Cross-referencing with known-good OBD2 applications or even physical sensors can help validate your data interpretation.
By venturing beyond standard OBD2 PIDs and exploring vehicle-specific CAN codes, you can significantly expand the data available from your vehicle. When paired with a compact and informative 2-inch gauge OBD2 reader, this opens up possibilities for custom dashboards and real-time monitoring of parameters crucial for performance, diagnostics, and a deeper understanding of your car’s inner workings. Whether you’re tracking oil temperature on the track or monitoring fuel levels on a long journey, unlocking CAN codes can provide valuable insights.
