OBDII (On-Board Diagnostics II) ports offer a wealth of vehicle data beyond generic engine codes. With Diy Obdii Dash Gauges, you can tap into hidden metrics like oil temperature and fuel level, displayed in real-time on custom dashboards. This guide explores how to find vehicle-specific CAN codes and display this data using an Arduino and an ELM327 OBDII adapter.
Finding Vehicle-Specific CAN Codes
Generic OBDII PIDs (Parameter IDs) provide basic information, but vehicle-specific CAN (Controller Area Network) codes unlock a treasure trove of detailed data. Online resources are key to discovering these hidden codes:
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Torque App Forums: The Torque app for Android has a large community actively sharing vehicle-specific PID and CAN code information. Searching for your car make and model often yields valuable results.
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Vehicle-Specific Forums: Online forums dedicated to your car model are invaluable resources. Members often share custom solutions for accessing hidden data, including CAN codes and Arduino sketches. Diesel truck forums are particularly rich in this information.
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ScanGauge X-Gauge PID Library: ScanGauge provides a comprehensive library of X-Gauge commands, including many vehicle-specific PIDs. While not directly CAN codes, they offer clues and potential starting points for your research. (http://www.scangauge.com/support/x-gauge-commands/)
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CAN Bus Sniffing: If online resources fail, you can directly sniff your vehicle’s CAN bus traffic to identify the desired data. This requires specialized hardware and software, with tutorials available online. (https://www.instructables.com/id/CAN-Bus-Sniffing-and-Broadcasting-with-Arduino/ )
Decoding and Displaying Data with Arduino
Once you have the correct CAN ID and PID, extracting the relevant data from the returned string requires careful analysis. The data is typically encoded in hexadecimal format. Pinpointing the correct bytes within the string often involves trial and error.
One effective method involves sending repeated requests to the OBDII adapter and logging the responses to the Arduino Serial Monitor. Graphing this data in a spreadsheet helps visualize changes corresponding to sensor readings. Comparing this data with a known good source, like the Torque app or a physical gauge, confirms your findings.
For instance, accessing oil temperature on a BRZ/FRS/GT86 requires sending a specific CAN header command using an ELM327 adapter:
runCommand("AT SH 7E0",data,20); //(FRS/gt86/brz specific CAN header)Then, query for the oil temperature PID:
status=getBytes("21","01",values,1);This example illustrates the process of sending commands and receiving data. Adapting this code for your specific vehicle and chosen PID is crucial for displaying the desired data on your custom dashboard. Experimentation and careful analysis are key to success in creating your own DIY OBDII dash gauges. By leveraging online resources and a bit of ingenuity, you can unlock valuable insights into your vehicle’s performance and create a truly personalized driving experience.
