Dodge 2009 Caliber SRT4 - Manual (Page 164)

TURBO BOOST GAUGE
Your vehicle is equipped with a boost gauge that indi-
cates the intake manifold pressure relative to barometric
pressure. The engine management system in your vehicle
intelligently regulates intake manifold pressure based on
environmental (ambient) and engine operating condi-
tions.
Turbo Boost Gauge
162 UNDERSTANDING YOUR INSTRUMENT PANEL