Digital Gauge Cluster

In the 2018 model year, Subaru refreshed the VA chassis WRX. The most noticeable changes were the updated front bumper, gauge cluster, and Multi-Function Display (MFD). Unfortunately, Subaru also made changes to the interior wiring harnesses. CAN bus is now filtered out of the OBD2 port, meaning data transfer through the port is limited. This change does not matter for most, but it causes a reduced data logging rate for people using a Cobb Accessport or similar device. Rather than the 50hz logging rate seen on 15-17 cars, my car only gets around 16hz. This results in many instances of missing or misaligned data.

In order to improve the logging rate, I needed to tap directly into the CAN wires somewhere other than at the OBD port. Fortunately, they are easily accessible behind the MFD. I tapped into the wires, made a simple ESP32 program, and was quickly able to read and write CAN frames. With a direct CAN connection, I could access all of the unfiltered data that I could not before. Now I had to figure out how to turn that data into the parameters I was used to reading. After many hours of CAN sniffing, I established a base set of definitions I could use for data logging. The project was complete. However, now that I’d gotten such high-level access to the car, I wanted to do more.

I created a digital gauge cluster in C++ using the QT framework. The program can read and write CAN frames to get necessary data and display it to the driver. Right now, it is just a copy of the stock cluster layout, but I plan to make more layouts. Since I can read everything the car does, I plan on adding some systems that Subaru did not provide from the factory. For example, auto rev matching, media controls, and navigation can be integrated directly into my digital cluster with relatively little additional investment.

This has been a very educational project for me, and I am excited to continue working on it.