I went to pass another vehicle last week and my truck lost power and would only idle very roughly....Shut the truck down and it would not start. I checked the codes and had a P0336 code. I replaced the Crank Position Sensor. Tried to start the truck up again and no fuel coming through the IP. I ended up replacing the IP with a reman(made it to 130k before first VP44)...Truck started up, took it for a test drive and any time I went over 1500RPM, RPM gauge would drop to 0. Checked the codes again and came up with P0336 P1475, P0122, P0602(expected due to SMARTY). Reset ECM back to stock, cleared the codes, started truck again and ended up with P1475 and P0336. Replaced the CKPS just to be sure it wasnt a faulty part. I continue to have the RPM gauge cut out at anything over 1500RPM. I checked all the other sensors and they were fine. Does the P1475(5V Aux Voltage High) mean my ECM is bad and I need to replace it? Dealership wants 1500 for a new one....Any ideas where I could pick one of these up?

 

I would definitely test the whole CKP circuit before condemning the ECM. There could be a corrupted ground or a short causing your problem. If you could find the diagnostic manual for that truck and follow the flowchart for that fault, it would help. A lab scope sure wouldn't hurt either- in a perfect world.