2012 kw t660 issues

[Waterloo]

Like RT stated, sounds like a lose wire or connection going to/from/at the ECM. Check the wires going in to the ECM and follow the harness back to look for possible causes. I know that what you are describing is common on older trucks, but worth taking a look at just the same. Then head to the battery box, check the battery connections and check for any lose of frayed wires there to start and then work towards ECM. Make sure the batteries are also secured down properly and not bouncing around in the box. Also check the grounds at the engine block and frame and the main power cables. You would have passed out seeing what the factory called cabling on my ProStar, I am surprised mine even ran it was that bad. The main starter cable had 10 inches of bare copper cabling exposed, no jacket at all. The rest of the factory cabling was in the same condition, both power and grounds, I had to replace it ALL. I have never seen anything like it. The truck went 700,000 miles like that and I was the first to catch it after I bought the truck.

One other thing too, I know that if voltage drops to I think around 10 or 11 volts off the alternator, that it will or can shut down the truck as the ECM needs a certain amount of continuous voltage to operate.

Another thing, there should be a cab or body controller in the cab of the truck somewhere, I don't know if that can cause an engine to do as you describe, but that would be another area I would check too for pinched or lose wiring. My body controller is located in the left hand floor kick panel of my ProStar and is really squeezed in there.

Hope that helps!