Instrument Cluster Gateway Function

Instrument Cluster Gateway Function

The instrument cluster incorporates a gateway function. The gateway function is the link between the vehicle bus systems and the audio system MOST ring. When the vehicle is unlocked, the instrument cluster receives a system 'wake-up' message on the CAN (controller area network) bus. This message is then passed to the integrated head unit (IHU) which then 'wakes-up' the MOST ring components by energizing the infotainment relay.

System Security
The gateway function stores a unique serial number for each component in the infotainment system. This new system, known as 'Security on MOST' replaces the radio codes used on previous audio systems.

During vehicle production, the serial number of each component is extracted from its memory and stored in the instrument cluster. At every subsequent ignition on cycle, the Integrated Head Unit (IHU) reads the serial number for each component and compares them to the stored serial numbers in the instrument cluster. If an incorrect code detected the MOST system will shut down and the infotainment system will not function.

If an infotainment component is replaced, T4 will be required to disable the security on MOST feature. A file is downloaded which extracts the new serial number from the replacement component and records it in the instrument cluster. T4 is used to re-enable the security on MOST feature and restore the system security.