ECM at startup, Peterbilt 579

[Rawze]

because it gives all the secondary systems a chance to do all their self-checks and establish communications to the ecm+cab controller without all the crazy strong voltage spikes off the starter due to cranking getting in the way.

these things aren't your grandma's 1970's station wagon,.. there are more computers and safety systems that need to boot up, than carter has liver pillz any more on these newer trucks.