Standard Corporate Protocol
WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
The Standard Corporate Protocol (SCP) is a communication language used by Mazda for exchanging bi-directional messages (signals) between stand-alone modules and devices. Two or more signals can be sent over one circuit.
Included in these messages is diagnostic data that is output over the BUS+ and BUS- lines to the DLC. This information is accessible with the WDS or equivalent.