C15 Acert BXS shuts off-throws no codes HELP!!!!

on a 379 peterbilt there is a two wire conector for constant ecm power supply from battery box to ecm, seen many problems with weatherpack connection, should be located at top of frame rail on left side above starter area, start truck and move connections and see if truck dies, if so, cut connection out and hard wire around, good luck.

 

Just had the same probelm the ecm ground wire was broke at the battery terminal it was a one piece terminal check the speed senor my be good bad

 

try running a wire to ecm pin 70, this is key power to the batteries with an alligator clip. run this for a few days see what happens if it helps you will at least have a direction. you need battery power to pins 52 and 53 battery ground to pins 65 and 67. I seriously doubt the ecm is bad. you might remove the fuse box flip it around and see if the wires at the lower ign breaker are not rusting off

 

I had an 05 bxs acert that had similar problems for a couple of months, then one day it died and never started again. At that point it did throw a code for something injector related, but I put a new ECM on and never had another problem. If you are confident your wiring is good that would be my guess, unfortunately it's pretty expensive to do a trial part changing with, but if you could find someone with a spare ECM to try for a bit to see what happens? Good luck!

 

You might try getting in touch with a Mr. Haney on this forum to get a pre-tuned ECM. He gets high ratings, and if you're going to spend some money anyway, may as well upgrade the horsepower while you're at it. Just an idea, don't know what you're into.

 

Something else for you to check, there should be a 5A fuse in the fuse box ( top row from memory ) that supplies power to the ECM, check the terminals are not corroded on that and its nice and snug. Also do the dash lights or anything else die when it does it ? I have seen problems like this before when i had a big footed driver kicking the fuse panels as he's dancing on the pedals.

 

The speedometer issue is the speed sensor in the tailshaft of the transmission. Eaton changed them to a cheap plastic housing that glues together. The glue breaks down at the seam where the top of the sensor housing is mated to the lower portion and allows moisture to enter the sensor. Corrosion builds internally in the sensor and degrades the sensor signal to the ECM and gauge. The first sign of this problem is erratic movements of the speedometer needle of the gauge.

The shutting off issue is one of a few things. The power supply from the batteries this usually stores a fault code in the ECM. The power supply from the ignition switch, this usually will not leave a fault code. The injector drivers in the ECM are failing. This is a common problem with the particular ECM you have, but this will also store a fault code. You could also have a cracked circuit board in the ECM that isn't allowing keyed power to be registered by the ECM at times. This would shut the truck down in the same fashion as turning the key to the off position. It wouldn't register a fault code, but at the same time you will not be able to communicate to the ECM with Cat ET either. Over the years I've run into a very few ECM with cracked or broken circuit boards in them. Usually when I do find one that is bad a function of the ECM doesn't work. Such as the jake will only work on two stages or the manual fan switch will not work, because the input signal isn't making it to the circuit board. I've never seen one do what you are describing.