- **Diagnostic requests are well covered.** Mitsubishi's MUT-III protocol is
KWP2000 over ISO 15765 (`0x21 <local id>` "mode 21" requests), and OBDb publishes
open, machine-readable definitions for many Mitsubishi ECUs. Those are the fast
path to named signals, and the ground truth for decoding the broadcast ones.
- **Standard OBD-II mode 01** (RPM 0x0C, speed 0x0D, coolant 0x05, …) works on any
car of this age and is what `obd-poller` should start with — all nine signals in
`schema/signals.json` are mode 01 PIDs.
## Sources
### Broadcast frames
| Source | What it has | Use to us |
|---|---|---|
| [ECUMASTER ADU application note, Evo X](https://www.ecumaster.cz/download/evoX.pdf) | Evo X OBD port at 500 kbps, pins 6/14, no terminator; a channel list (rpm, speed, tps, clt, wheel speeds, indicators, lights, gear) but the IDs only inside their `.canx` file | Same bus conventions as ours; no IDs |
| [EvolutionM "Evo X real CAN packets"](https://www.evolutionm.net/forums/evo-x-engine-management-tuning-forums/552550-evo-x-real-can-packets.html) (forum, blocks automated fetch) | Evo X: RPM in `0x308` bytes 1–2; throttle in `0x210` bytes 0–1 | `0x210` exists on our bus too, but with a **different layout** (6 bytes; the RPM-like value is in bytes 4–5). Evo X IDs do not transfer |
| [awesome-automotive-can-id](https://github.com/iDoka/awesome-automotive-can-id) | Index of public CAN ID collections; Mitsubishi: Lancer 2008 ([habr, RU](https://habr.com/ru/post/448658/)), i-MiEV | Lancer article covers diagnostics, not broadcast (below) |
| [billyjack2/CAN-DBC-Collection](https://github.com/billyjack2/CAN-DBC-Collection) `MITSUBISHI/COLT/can1v3.dbc` | AiM logger driver "Mitsubishi Colt" as a DBC: wheel speeds `200`/`208`, pedal `210` byte 2, brake switch `300`, rpm `308`, speed and fuel `412`, battery `416`, coolant `608` | The EU Colt / forfour engine-side set (it matches the forfour notes below), **not the Z27's**: of its IDs only `210` and `300` exist here, and neither fits — `210` byte 2 stays `08` through a throttle blip while bytes 4–5 follow rpm; `300` is 4 bytes, not 8 |
| [I2000C/SmartCruiseControl](https://github.com/I2000C/SmartCruiseControl) `doc/CAN bus reverse engineering.md` (MIT) | Smart forfour 454, 2006, **1.5 CDI diesel**, sniffed: ~30 IDs with lengths and byte notes. Decoded: `09E` odometer (bytes 4–6, 0.1 km), `200` handbrake + three speeds (×0.05 km/h, big-endian), `208` brake intensity + speeds, `210` pedal (byte 2), `212` pedal sensor 2, `308` rpm (bytes 1–2), `408` fuel litres, `40C`/`412` dash speed, `416` battery (0.1 V), `423` ignition / lights / indicators / doors bitfield, `608` coolant (−40) and fuel rate | **The closest relative found.** Body and chassis frames match ours: `0C0` (5 bytes, byte 3 always `07`, byte 4 counter; ours `6DFF0007xx`), `119` (byte 5 `08`), `312` (four 16-bit words), and `2F1`, `300`, `443`, `423` exist on both. The engine-side frames do not (`308`, `608`, `200`/`208` absent here; `210`, `423` other lengths and layouts) — plausibly because that car's engine ECU is Mercedes' diesel one and ours is Mitsubishi's 4G15T |
The Z27 Colt is a 2002 platform shared with the smart forfour (W454); the CZT /
Ralliart's 4G15T is also the forfour Brabus engine, and parts listings show the
sharing reaches the electrics (Z30 engine ECUs carry Mercedes-style `A135…` part
numbers; the steering rack is the 454's). The forfour notes bear that out for the
body bus. Their layouts are the first hypothesis for every shared ID, and their
| [EvoScan](https://evoscan.com/) | Commercial logger with MUT-III support for the EU Colt CZT / Ralliart (4G15T). Its parameter definitions are the most complete source for engine mode-21 requests on our exact engine; not open |
| [EcuTek Colt suite](https://www.tpwengineering.com/products/ecutek-vehicle-tuning-mitsubishi-colt) | Confirms the 2005+ EU Colt CZT / Ralliart ECU speaks CAN for flashing; nothing published |
OBDb's definitions are from newer Mitsubishis (roughly 2008 on). Whether the Z27's
meter and A/C units answer at the same addresses is a question one listen-only
look at the bus during a MUT-III session — or one careful request — would settle.
## What the first capture shows
`z27ag-20261009-163736-ign.log`: engine idling, parked, a light touch of
throttle around t ≈ 4–5 s. 27 periodic IDs, ~893 frames/s. Every observation
below is a candidate until checked against OBD-II mode 01 in the same recording.
| ID | Period | Candidate |
|---|---|---|
| `210` | 20 ms | **Engine speed**: bytes 4–5, big-endian, 1 rpm/bit — ~845 at idle, rising to ~900 with the throttle blip and back |
| `13D` | 20 ms | **Engine speed again**: bytes 0–1, little-endian, ≈ 2×`210`'s value (0.5 rpm/bit?) — moves in lockstep with it |
| `312` | 20 ms | Four 16-bit big-endian words near 0x07B0–0x0940, all noisy, two follow the blip. Sensor values; load or pressure, not wheel speed (parked) |
| `449` | 200 ms | Bytes 0, 1, 3 = 0x6F, 0x5F, 0x71: with the usual −40 offset, 71, 55, 73 °C — temperatures of a warm engine |
| `0C0` | 10 ms | Byte 4 low nibble a 4-bit rolling counter; high nibble looks like a checksum |
| `119`, `149`, `156` | 20 ms | Byte 6 low nibble a rolling counter, byte 7 a checksum (neither plain sum nor XOR) |
| `149` | 20 ms | Bytes 0 and 4 noisy around a centre: an inertial sensor (yaw / lateral g) is the usual owner of such a frame |
| `710`–`713` | 200 ms | Slow, mostly constant: body/meter status |
Counters and checksums matter only for transmitting, which is out of scope. The
fits OBD-II replies for powertrain signals and phone sensors for body ones (GNSS
plays that part here); [CAN-D](https://www.ornl.gov/publication/can-d-modular-four-step-pipeline-comprehensively-decoding-controller-area-network-data)
and [ByCAN](https://arxiv.org/html/2408.09265v1) find signal boundaries from bit
flip rates, then byte order and signedness, then match. None reads our logs; the
