Circuit Description
WARNING: This page is about a different car, the 1998 Cadillac Eldorado and 1998 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Modules connected to class 2 serial data line, monitor the line for serial data communications during normal operation. SDM sets DTC U1064 when no SOH messages detected on class 2 data line.