code p0740 and p1860

[Juancm]

i just finish puting a remote starter on a 98 blazer lt and the havent ran for
a week and code p0740 and p1860 poped up .i took it out for a test drive
and the tranny shift find and it has power ,when you start off.now i have heard that the ignition switch could be the problem.is there any way to check if the ignition is the problem? one more problem my speedometer doesnt work since i got the car .i put in my scanner and it read how fast i was going ,so is not the speed sensor. but i need a diagram of which wire is the speedometer or the wire that goes from the computer of the car to the inside