07 Advanced
CAN protocol
Bus layout, standard dash IDs, and talking to other modules.
7 min readUpdated 2026-08
CAN 1 lives on B17 (H) and B16 (L). 1 Mbit/s is the Race Core default for ECU–dash–wideband. Some OEM bodies want 500 kbit/s; pick one rate for the whole bus or use a gateway.
Physical
- Twisted pair. 120 Ω at each end. Two terminators, not one per node.
- Common ground between modules. CAN is differential, but modules with a 40 V ground offset will still drop frames.
- Keep the stub to a wideband or a dash under a few hundred millimetres if you can. A 3 m unterminated spur is a reflection generator.
What usually rides the bus
| Node | Typical use |
|---|---|
| Digital dash | RPM, MAP, CLT, AFR, gear, warnings — Race Core broadcasts a rusEFI-compatible set; dashes like uaDASH / Realdash consume it. |
| CAN wideband | Lambda in, often also heater status. |
| GPS module | Speed for traction / logging when you have no undriven ABS pin. |
| OEM body / dash | BMW E46/E90, VAG, Fiat, RX-8, Honda K, 350Z, Mercedes — enable the matching CAN module. |
| PDM / switch panel | Keypad to Lua or native CAN inputs. |
Enable the matching CAN channel and bit rate in TunerStudio. If the dash shows RPM = 0 while TunerStudio shows RPM, the dash is on the wrong rate, the wrong endian, or a different ID map — not a trigger problem.