Start with EV Open CAN

Step 1 of 8

Welcome

One decision at a time. Your answers create a personal setup plan.

Start without the information overload

This guide explains what the project does, helps you choose compatible hardware, shows the safe installation area, and gives you the correct build and first-start path.

This is experimental vehicle-network hardwareCAN connects safety-critical vehicle computers. Begin on a bench, keep transmission disabled, and never guess a connector, bus, pinout, bitrate, or vehicle hardware generation.

Learn and observe firstRecommended. Start with the dashboard or a logger while CAN transmission stays stopped. Prepare for plugins laterFollow the same safe start, then learn how reviewed plugin rules work after traffic is verified. Record with SavvyCANChoose a dashboard board that supports read-only GVRET logging over USB serial. Bench research onlyBuild an isolated CAN setup without installing anything in a vehicle.

I understand the safe starting point.
I will begin with injection stopped and verify the exact vehicle documentation before connecting to a live bus.

Tell us what you are working with

The model and build date affect harnesses and installation areas. The Autopilot computer generation affects the firmware vehicle mode. Do not infer one from the other.

Model 3Sedan, including pre-refresh and refreshed interiors. Model YCrossover. Connector and trim details can differ by build date. Model S or XUse model-specific service information. Do not reuse Model 3 or Y guidance. Bench onlyNo vehicle installation. Use an isolated harness and current-limited supply.

Build year Vehicle hardware mode

Not sure whether the car is Legacy, HW3, or HW4?Stop here and verify it from authoritative vehicle information or service documentation. Model year alone is not enough. The final plan will keep a visible reminder until you select a confirmed mode.

Choose the physical device

For a first build, an integrated ESP32 and CAN board avoids loose transceiver wiring. Advanced boards remain available when you already understand CAN electronics.

Beginner friendly

M5Stack AtomS3 Mini CAN BaseCompact dashboard board with an integrated CAN base.

Environment: m5stack-atoms3-mini-can-base

Simple alternative

M5Stack Atom CAN BaseSmall integrated option supported by the dashboard firmware.

Environment: m5stack-atomic-can-base

Terminals and enclosure

Waveshare ESP32-S3 RS485/CANIntegrated CAN board with screw terminals. Confirm the exact terminal labels before wiring.

Environment: waveshare_ESP32_S3_RS485_CAN

Advanced

Custom ESP32 plus transceiverOnly choose this when logic voltage, transceiver power, termination, GPIOs, and SPI or TWAI wiring are already understood.

Environment: esp32_twai or esp32_ext_mcp2515

Collect the parts before opening the car

A calm installation starts with every part on the table. Check each item as you prepare it.

Selected supported board
The exact board must match the firmware environment. Known-good USB data cable
Some charging cables provide power but cannot flash firmware. Vehicle-specific plug-in harness or adapter
For a beginner, use a verified connectorized harness instead of tapping unidentified wires. Non-conductive enclosure and secure mounting
The board must not move, rattle, short against trim, or interfere with pedals, seats, airbags, or HVAC. Laptop with PlatformIO or a matching release image
Keep a USB recovery path available even when OTA will be used later. Safe first-test equipment
Prefer an isolated bench harness, current-limited supply, and an independent CAN logger.

Do not buy or connect a harness based on a similar-looking photo.Vehicle connectors and network assignments can change between models, factories, and build dates. Match the exact vehicle service information.

Understand where the device belongs

The visual below points to a general installation zone. It deliberately does not claim that one connector or wire is correct for every vehicle.

Secure behind removable trimMount the enclosed board so it cannot move or touch metal.

Keep USB service accessLeave enough cable and access to recover or reflash the board.

Avoid safety equipmentNever route near airbags, seat rails, steering mechanisms, pedals, or high-voltage wiring.

Verify Party CANFor the supported hands-on-wheel experiments, verify Party CAN from exact service documentation before connecting.

The illustration is not a pinout.Open the correct Tesla electrical reference or service documentation for the exact model and build date. Confirm CAN H and CAN L, voltage, termination, and 500 kbit/s traffic with a listen-only tool.

Model 3 electrical reference CAN safety guide

Put the correct firmware on the board

The board environment and vehicle mode in your plan are used below. Never flash an image intended for another board.

BoardSelected hardware

EnvironmentPlatformIO target

Vehicle modeMust be verified

Option A: matching release image

Open the latest release and download the artifact whose board name matches your selected environment. Keep the USB cable ready in case recovery is needed.

Open latest release

Option B: build from source

First flash on the benchPower the board over USB, confirm it starts, and find its hotspot before connecting it to the vehicle network.

Bring it online in the safest order

This sequence keeps software, power, and vehicle wiring problems separate, so a newcomer can identify where something went wrong.

Bench power first: connect only USB and confirm the board boots.
Join the hotspot: connect your phone or laptop to the configured EV Open CAN access point.
Open the dashboard: browse to http://192.168.4.1/.
Keep injection stopped: do not install or enable a transmitting plugin.
Connect the verified harness: only after the exact bus, connector, voltage, and polarity have been confirmed.
Observe traffic: received-frame count should increase and frame age should remain fresh. Resolve bus-off, recovery, or missing traffic before going further.

Dashboard opensPower and WiFi are working.

RX count changesThe selected CAN interface sees valid frames.

Injection stoppedThe correct state for a first session.

No dashboard?Check USB power, serial output, hotspot name, and the exact firmware environment. No CAN frames?Disconnect and verify the bus, H/L polarity, transceiver power, bitrate, termination, and GPIO defaults.

Your personal starting plan

Save or print this checklist. It contains your choices and the safe order for getting started.

Onboarding complete means ready to begin learningIt does not mean a live vehicle installation or transmitting rule has been validated. Continue with the build, dashboard, safety, and plugin documentation in that order.

Build and flash Dashboard guide CAN safety Plugins