Circuit/System Description

The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM) or the powertrain control module (PCM). The ECM/PCM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The ECM then sends the vehicle speed signal information via the GMLAN serial data circuit to the IPC. The IPC displays the vehicle speed based on the GMLAN serial data message from the ECM.