Hooked up a scan tool to my '04 Burb (3/4 ton) 6.0L and found that the guage on the dash was approx 12 degrees off from what the PCM was seeing. When the truck got a hair from 210, the PCM stated 198. About 10 minutes after starting the truck, the gauge stated about 180 registering on the dash gauge, the PCM had it at appox 147.

Anyone else find a disparity between what the PCM states the coolant temp is compared to the dash gauge?

on the 454 guage reads at a different place from scan tool, scan tool reads from thermostate( what computer is seeing ) and guage reads from sensor in side of block