Garmin G1000 Pilot's Manual page 129

Normally Aspirated Aircraft
When a cylinder peaks, its peak is represented by a
hollow block on the EGT Bar Graph. The EGT Readout
for the peaked cylinder, indicated in cyan, appears directly
beneath the bar graph. The system automatically switches
to the first peak obtained and displays the temperature
deviation from peak (∆PEAK) in degrees Fahrenheit
below the EGT Readout.
Turbocharged Aircraft
Leaning is done with reference to the Turbine Inlet
Temperature (TIT) Indicator. When the temperature
peaks, the numeric readout (∆PEAK) appears below
the TIT Indicator and displays the difference between
peak and current TITs, in degrees Fahrenheit. If a peak
is not displayed, underscores are shown until one is
established.
190-00498-00 Rev. A Garmin G1000 Pilot's Guide for Cessna Nav III
ENGINE INDICATION SYSTEM
Exhaust Gas
Temperature
Bar Graph
Temperature
Deviation
From Peak
CHT Readout
For Selected
Cylinder
Fuel Quantity
Indicator
Figure 6-6 Lean Page (172)
Tachometer
Hollow Block
Representing Peak
EGT Readout
For Selected
Cylinder
Cylinder Head
Temperature
Bar Graph
Fuel Flow
6-7