Instrument Panel Cluster (IPC) Description and Operation: Speedometer

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The instrument panel cluster (IPC) displays the vehicle speed as determined by the engine control module (ECM)/powertrain control module (PCM). The ECM/PCM converts the data from the vehicle speed sensor to a 4,000 pulses/mile signal. The IPC uses the vehicle speed signal circuit (4,000 pulses/mile), class 2 message from the ECM/PCM in order to calculate the vehicle speed. If the IPC detects a malfunction in the vehicle speed signal circuit from the ECM/PCM, the IPC uses the class 2 message from the EBCM, indicating the vehicle speed as a backup. If the speedometer reaches (108 mph) the fuel will shut-off, and it will turn back ON when the speedometer is at (106 mph). The speedometer displays either miles or kilometers as requested by the activation of the english/metric button on the driver information center (DIC). The associated indicator (km/h or mph) illuminates.