This Technical Information Report defines the General Motors UART Serial Data Communications bus, commonly referred to as GM UART. This document should be used in conjunction with SAE J 2534-2 in order to enhance an SAE J 2534 interface to also provide the capability to program ECUs with EM UART.

SAE J 2534-1 includes requirements for an interface that can be used to program certain emission-related Electronic Control Units (ECUs)as required by U.S. regulations, and SAE J 2534-2 defines enhanced functionality required to program additional ECUs not mandated by current U.S. regulations. The purpose of this document is to specify the requirements necessary to implement GM UART in an enhanced SAE J 2534 interface intended for use by independent automotive service facilities to program GM UART ECUs in General Motors vehicles.