Instrument Panel Cluster (IPC)
Instrumentation, Message Center and Warning Chimes
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
NOTE: When installing a new Instrument Panel Cluster (IPC), it is necessary to upload the module configuration to the scan tool. Following installation of the IPC, download the module configuration from the scan tool into the new IPC. Refer to Information Bus to carry out the Programmable Module Installation (PMI). It is also necessary to carry out a parameter reset procedure whenever a new IPC or PCM is installed. Refer to Antitheft and Alarm Systems. Programming and Relearning Passive Anti-Theft System (PATS)
The IPC utilizes a microprocessor to control the gauge, indicator, message center and warning chime functions. Data is sent to the IPC over the Medium Speed Controller Area Network (MS-CAN) and the High Speed Controller Area Network (HS-CAN) bus lines and through hardwired circuitry from individual components. The IPC uses each input to output an action to the gauges or indicators.
It is very important to understand:
- where the input originates.
- all the information necessary in order for a feature to operate.
- which module(s) receive(s) the input or command message.
- does the module which received the input control the output of the feature, or does it output a message over the communication network to another module.
- which module controls the output of the feature.
Instrument Panel Cluster (IPC)
IPC Gateway Function
The IPC acts as a gateway module by receiving information in one format and transmitting it to other modules using another format. For example, the IPC receives the vehicle speed data from the PCM over the HS-CAN, converts the data into an MS-CAN message and sends (gateways) the message to other network modules such as the Audio Control Module (ACM) and the SJB. This enables network communication between modules that do not communicate using the same network (HS-CAN or the MS-CAN).
IPC Network Messages
The IPC uses input messages from other modules to control the gauges, informational indicators, message center indicators and warning indicators over the communication networks. If a required message is missing or invalid for less than 5 seconds, the gauge or indicator that requires the message remains at the last commanded state based upon the last known good message. For example, if the brake status message is missing for less than 5 seconds and the brake warning indicator was on, the indicator remains in the on state until the next good message is received. If the message remains missing or invalid for greater than 5 seconds, the IPC sets a U-code DTC and the output becomes a default action for the indicator or gauge. Each indicator or gauge utilizes a different default strategy depending on the nature of the indication. Refer to the normal operation descriptions located before each individual pinpoint test for further description of the default action specific to each indicator or gauge. If the messaged input to the cluster returns at any time, the normal function of the gauge or indicator resumes.
NOTE: Whenever a network message is suspected as missing and confirmed by a missing message DTC (U-code), it is important to look for other symptoms that may also be present in the IPC and throughout the vehicle. Once a DTC is set in the IPC, it may be helpful to review the complete message list available in Information Bus to see what other modules also rely on the same message and run the self-test for those modules. If the message is missing from other modules, the same DTC may also be set in those modules. Confirmation of missing messages common to multiple modules may indicate that the originating module is the source of the concern or the communication network may be experiencing some problems.
IPC Configuration
The IPC contains items that are configurable. While some configurable items are customer preference items configured using the scan tool, most items are configured at the end of the line production and only available for configuration through the PMI procedure. Refer to Information Bus.
IPC Configuration Parameters:
IPC Prove-Out
The IPC carries out a display prove-out to verify that all module controlled warning/indicator lamps and monitored systems are functioning correctly within the IPC. When the ignition is in the ON mode with the engine off, the indicators illuminate to prove-out according to the following table:
