PACCAR MX-13 problem

[tree98]

Not sure why you would take the ECM off?? There isn't really any way to bench test an ECM so whoever is telling you they can do it is lying to you.

When the dealer suspects a bad ECM they put a known good one on the engine and see if the problem is solved, they don't and can't "test" an ECM.

You Said these codes were in the cab controller, you do know the cab controller and ECM are 2 different things right?