Principles of Operation: Notes

WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

The instrument cluster is a configurable, hybrid electronic cluster (HEC) that contains a microprocessor, gauges, indicator lamps, and internal circuitry. The instrument cluster is non-repairable with the exception of the instrument cluster lens and indicator bulbs. The instrument cluster uses hardwired circuitry, the controller area network (CAN) and the universal asynchronous receiver transmitter (UART)-based protocol (UBP) communication networks. Communication using the CAN transmits and receives data between the instrument cluster and the powertrain control module (PCM), and the anti-lock brake system (ABS) module. Communication using the UBP network uses data transmitted and received by the instrument cluster, and the electronic automatic temperature control (EATC), vehicle security module, and the driver seat module. The restraint control module (RCM) and the parking aid module communication is on the international standards organization (ISO) network. For additional information regarding the CAN, UBP and ISO communication networks, refer to MODULE COMMUNICATIONS NETWORK .

It is very important to understand:

Where the input originates from.
All the information necessary in order for a feature to operate.
Which module(s) receive(s) the input or command message.
Whether the module which received the input controls the output of the feature, or whether it outputs a message over the communication network to another module.
Which module controls the output of the feature.