TrailBlazer 2WD V8-6.0L VIN H (2006)
Tachometer: Description and Operation
TACHOMETER
The instrument panel cluster (IPC) displays the engine speed based on the information from the powertrain control module (PCM). The PCM converts
the data from the engine speed sensor to a 2 pulses/engine revolution signal. The IPC uses the engine speed signal circuit (2 pulses/engine revolution)
from the PCM in order to calculate the engine speed. If the IPC detects a malfunction in the engine speed signal circuit, the IPC uses the class 2 message
from the PCM indicating the engine speed.