What are the OBD-II communication protocols?
Quick Answer
Five protocols: J1850 PWM (Ford), J1850 VPW (GM), ISO 9141, ISO 14230 (KWP2000), and CAN (mandatory since 2008).
There are five OBD-II communication protocols: SAE J1850 PWM (used primarily by Ford), SAE J1850 VPW (used primarily by GM), ISO 9141-2 (used by Chrysler and many Asian/European vehicles), ISO 14230-4 (KWP2000, used by many Asian/European vehicles), and ISO 15765-4 (CAN, mandatory on all US vehicles from 2008+). Modern vehicles predominantly use the CAN protocol. When purchasing a scan tool, make sure it supports all five protocols for universal compatibility.
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