Protocol
CAN and CAN FD in diagnostics (ISO 15765)
CAN is the bus a car's ECUs use to talk to each other, and diagnostics has run over it since the mid-2000s; ISO 15765 defines how diagnostic messages travel on it. CAN FD is its evolution: frames of up to 64 data bytes and a faster data phase.
Reviewed by Daniel Morales, founder of Reprorace SL, on
Key facts at a glance
| Protocol | Standard | J1962 pins | Speed or link | ECO-LITE | ECO-LITE TOOL | ECOPRO Gen4 |
|---|---|---|---|---|---|---|
| CAN | ISO 15765-4 · ISO 11898 | 6 and 14 (2nd channel on 3 and 11; classic CAN on 1 and 9) | 125, 250 and 500 kbit/s | Yes: 2 channels and pins 1/9 | Reproduces the vehicle's | Multichannel |
| CAN FD | ISO 15765 · ISO 11898-1 | 6 and 14; 3 and 11 | Data phase as the vehicle sets it | Yes, on both channels | Reproduces the vehicle's | Multichannel |
Data from the device catalog and the standards cited. The devices are in pre-production: figures may be adjusted after the first units have been validated.
When you need it
- Any modern car or van: OBD diagnostics runs over CAN on pins 6 and 14
- Recent vehicles whose ECUs already speak CAN FD
- Cars with a second diagnostic bus on pins 3 and 11, such as Ford's MS-CAN
- Vehicles with CAN on pins 1 and 9, common on some trucks
Which Diaglana device covers it, and its limits
- ECO-LITE
- Two CAN FD channels (pins 6/14 and 3/11) and one classic CAN channel on pins 1/9, at 125, 250 or 500 kbit/s. The 1/9 channel doesn't support CAN FD.
- ECO-LITE TOOL
- Reproduces the remote car's CAN buses on its female socket, so your tool sees them as if it were plugged into the car.
- ECOPRO Gen4
- Several CAN and CAN FD channels. In development.
Frequently asked questions
What's the difference between CAN and CAN FD?
CAN FD carries up to 64 data bytes per frame, against 8 for CAN, and can speed up the data phase. For diagnostics, that means faster reads and flashing on the vehicles that use it.
Does my car use CAN FD?
It depends on the make and model. ECO-LITE detects the protocol when it connects, without blind trial and error.
What is ISO 15765?
The standard that defines how diagnostic messages run over CAN: the transport layer that splits long messages (ISO-TP) and, in part 4, the requirements for emissions diagnostics.
Why do some cars have CAN on other pins?
The J1962 socket reserves pins 6 and 14 for diagnostic CAN, but manufacturers use spare pins for extra buses. That's why ECO-LITE has channels on 3/11 and 1/9.
Want to try it in your workshop?
Check the device page for the full specifications, or buy in the shop at the final price.