Tachometer

The tachometer displays the engine speed in RPMs. The engine RPM is taken from the Powertrain Control Module (PCM) via the class II serial data line. The instrument cluster compares the engine RPM data with 16 point look-up table in order to determine needle deflection. A smooth filter secures a continuous response. The instrument cluster drives the tachometer gauge to 0 RPM if the following conditions occur:
^ The engine RPM data is lost.
^ The PCM is in a state of health fault.