System Operation: Tachometer
WARNING: This page is about a different car, the 2017 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The tachometer is a virtual gauge. The IPC requires 2 messages to operate the tachometer. The first is the engine rpm data message and the second is an engine active status message.
The IPC receives the engine rpm data message and the engine active status message from the GWM over the HS-CAN3. The GWM receives the engine rpm data message and the engine active status message from the PCM over the HS-CAN1.