Circuit Description

The instrument panel module (IPM) sends cruise control data to the engine control module (ECM). The data is sent to the ECM through a communication network called the GM local area network (LAN). Two circuits are used to communicate LAN data between the ECM and IPM. A fault in the LAN will not cause DTC U0423 to set by itself. If a LAN fault occurs, other DTCs will set in addition to DTC U0423.

If the ECM receives invalid cruise control data from the IPM, this DTC sets.