SAE J1587 diagnostic protocol runs over J1708 RS-485 physical layer using a round Deutsch or rectangular connector on heavy-duty commercial vehicles for reading fault codes and engine parameters before OBD-II.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | J1708+ | J1708 bus positive | BUS |
| 2 | J1708- | J1708 bus negative | BUS |
| 3 | GND | Ground | GND |
SAE J1587 diagnostic protocol runs over J1708 RS-485 physical layer using a round Deutsch or rectangular connector on heavy-duty commercial vehicles for reading fault codes and engine parameters before OBD-II.