Operation - Data Bus Communication Receive - Pcm Input
WARNING: This page is about a different car, the 2004 Dodge SX and 2004 Dodge Neon. However, it is still accessible from the selected car via links, so may be relevant.
The PCM uses the SCI communication bus to preform engine diagnostics and flash operations. The transmission side of the PCM uses the SCI communication bus to flash new software. However, diagnostics is performed via the vehicles J1850 bus for the transmission side of the PCM.