What is the pyrometer used for?

[Redland1]

(10-18-2021 )tree98 Wrote:  If your engine is demandated, the ecm can no longer keep exhaust gas temperatures in check so you need a way to keep an eye on it. If Temps start getting to high you back off the throttle/downshift.

They are also very handy for troubleshooting things like exhaust restrictions and catching leaky doser injectors before they melt down your doc/dpf and cook your turbo.

What I have is an 04’ cm870 with EGR.Is it worth having one if it’s not demandated?