Prior to 2008, OBD-II had several allowed wire protocols - SAE J1850 PWM (Ford), SAE J1850 VPW (GM), ISO 14230 KWP2000 (most other vendors), or ISO 15765 (OBD o

Prior to 2008, OBD-II had several allowed wire protocols - SAE J1850 PWM (Ford), SAE J1850 VPW (GM), ISO 14230 KWP2000 (most other vendors), or ISO 15765 (OBD over CAN). In 2008, the US requirement switched to exclusively ISO 15765 OBD over CAN.