Chlorophyll — Open-source TCU for the Nissan Leaf AZE0 (2015)

Status: very early / WIP — nothing works yet. Documentation under verification.

Replacement TCU (Telematics Control Unit) for the Nissan Leaf AZE0, based on an ESP32-S3 + LTE modem. The original TCU (type GNOV1N, Continental) is 2G-only, and the Nissan CARWINGS / NissanConnect EV backend it talked to is gone — so the factory telematics are dead either way. This project replaces the modem with LTE and the backend with a self-hosted OpenCARWINGS server.

Goal: a home-built TCU that speaks the CARWINGS protocol to a self-hosted OpenCARWINGS server over a modern IP stack (LTE), while remaining compatible with the original navigation unit.

Target architecture

                 ┌──────────────────────── Vehicle ─────────────────────────┐
                 │                                                          │
 ┌────────────┐  │  USB 1.0 (M68)   ┌──────────────────────┐   EV-CAN       │
 │  AV unit   │◄─┼─────────────────►│      Chlorophyll      │◄──────────────┼──► VCM / HVBAT / OBC
 │ (navi)     │  │  AT +XNAD_*      │  ESP32-S3 + LTE modem │   (TWAI)      │
 └────────────┘  │                  └──────────┬───────────┘                │
                 │       12V (M67) ────────────┤                            │
                 └──────────────────────────── │ ──────────────────────────-┘
                                               │ LTE (TCP :55230)
                                               ▼
                                  ┌─────────────────────────┐
                                  │   OpenCARWINGS server   │
                                  │      (self-hosted)      │
                                  └─────────────────────────┘

Details: docs/architecture.md

Roadmap

• Phase 0 — Python client for the server protocol, tested against scripts/test_server.py from the nissan-leaf-tcu repo and a local OpenCARWINGS server. Zero hardware: validate the protocol understanding (port 55230, packets, auth) before touching a soldering iron.
• Phase 1 — ESP32-S3 + LTE hardware: remote A/C, charge control, telemetry (SOC, range) over EV-CAN. The bare minimum to get the app features back.
• Phase 2 (research) — Navi screen services by emulating the original USB link (AT +XNAD_* commands). Feasibility not demonstrated.

Documentation

Document	Contents
architecture.md	System overview
protocol-server.md	TCU ↔ server protocol (port 55230)
protocol-navi-usb.md	TCU ↔ AV unit USB link (AT +XNAD)
evcan-telemetry.md	EV-CAN frames to read for telemetry
pinout.md	M67 / M68 / M113 connectors
hardware.md	Proposed BOM, power budget
firmware-findings.md	What the firmware dump reveals (strings)
reverse-engineering.md	Methodology and credits

Epistemic stance: every technical claim in this documentation carries a status marker — [VERIFIED: source], [TO CONFIRM: source], [TO MEASURE] or [TBD]. Anything without a VERIFIED marker must not be taken for granted. Do not wire anything based on a [TO CONFIRM].

Legal notice

• This project does not redistribute any proprietary firmware from Nissan/Continental. Analyses rely on work published in third-party repositories, referenced in references/, never copied here.
• All code in this repository is original.
• Use at your own risk. Working on a vehicle's wiring and CAN bus can damage the vehicle or create a safety hazard. No warranty.
• Sustainability / right-to-repair project, not affiliated with Nissan, Continental, or any manufacturer. Trademarks belong to their owners.

Credits

• developerfromjokela — TCU reverse engineering (nissan-leaf-tcu) and the OpenCARWINGS server.
• Mickey Shkatov and the DEF CON 25 team — foundational work on Leaf telematics security.
• The MyNissanLeaf community — years of collective documentation.

License

GPLv3. Deliberate choice: this project exists to extend the life of vehicles whose manufacturer abandoned their services. Copyleft guarantees that any improvement or derivative (commercial included) stays open and benefits Leaf owners, rather than being closed off. If you want to embed this code in a closed product, this is not the right repository.