Tach Signal - Range Active/Inactive

This data indicates whether the Body Function Controller (BFC) is acknowledging a tachometer signal message at the Instrument Cluster via the Serial Peripheral Interface (SPI) serial data line. Active, is displayed if the Body Function Controller (BFC) is measuring a tachometer signal message at the Instrument Cluster via the Serial Peripheral Interface (SPI) serial data line. Inactive, is displayed if the Body Function Controller (BFC) is not measuring a tachometer signal message at the Instrument Cluster via the Serial Peripheral Interface (SPI) serial data line. The Instrument Cluster receives a discrete tachometer signal from the Powertrain Control Module (PCM). The Instrument Cluster calculates the engine RPM based on the tachometer input and drives the tachometer gage. The Instrument Cluster also determines if the discrete hardware tachometer input is toggling, and sets a bit in the Serial Peripheral Interface (SPI) data return line to the Body Function Controller (BFC).