Module, Instrument Panel Cluster: Operation

WARNING: This page is about a different car, the 2018 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC) is designed to allow the vehicle operator to monitor the conditions of many of the vehicle components and operating systems. The gauges and indicators in the IC provide valuable information about the various standard and optional powertrains, fuel and emissions systems, cooling systems, lighting systems, safety systems and many other convenience items. The IC is installed in the instrument panel so that all of these monitors can be easily viewed by the vehicle operator when driving, while still allowing relative ease of access for service.

The microcontroller-based IC hardware and software uses various inputs to control the gauges and indicators visible on the face of the IC. These inputs are in the form of electronic messages that are transmitted by other electronic modules over the Controller Area Network (CAN) data bus. Refer to COMMUNICATION, OPERATION .

The IC microcontroller smooths the input data using algorithms to provide gauge readings that are accurate, stable and responsive to operating conditions. These algorithms are designed to provide gauge readings during normal operation that are consistent with customer expectations. However, when abnormal conditions such as high coolant temperature occur, the algorithm can drive the gauge pointer to an extreme position and the microcontroller can sound an audible alert through the on-board audible tone transducer to provide distinct visual and audible indications of a problem to the vehicle operator. The IC may also produce audible warnings on behalf of other electronic modules in the vehicle based upon electronic tone request messages received over the CAN data bus. Each audible warning is intended to provide the vehicle operator with an audible alert to supplement a visual indication.

The IC circuitry operates on battery current received through a non-switched fused B(+) circuit, and on battery current received through a fused ignition output (run) fuse on a fused ignition output (run) circuit. This arrangement allows the IC to provide some features regardless of the status of the ignition switch, while other features will operate only when the status of the ignition switch is ON. The IC circuitry has a path to ground at all times through a takeout of the instrument panel wire harness that is secured to the instrument panel support structure.

The IC also has a self-diagnostic test capability which will test each of the CAN bus message-controlled functions of the IC by lighting the appropriate indicators, positioning the gauge needles at several predetermined calibration points across the gauge faces and illuminating all segments of the electronic display unit. The electronic display unit will also display the software version used in the IC. Refer to DIAGNOSIS AND TESTING .