No Crank, low amp/voltage crank caused electrical fault

Hello guys, Heavy D, if you are out there this is for you! I have a 2016 Prostar with the ISX15 and Eaton 10 speed Auto Trans (Push Button). The truck batteries were low and there was a very slow crank. I hooked a jump box up and still had a slow crank or a low voltage/amp crank. The engine would slowly turn over but not fast enough to fire. After trying several times, the key was left in the crank position for too long resulting in an electrical fault along with ABS module message coming on in the cluster message center. When this happened, the truck will no longer turn over. The batteries were changed, all fuses/relays were checked but still no crank. Truck was scanned, there were codes that made no sense, for example output shaft speed sensor, The codes would clear but come back within 3 seconds using a scanner. The Batteries have been disconnected multiple times over about a week, trying to reset the modules, with no luck. (Electrical fault still shows up) The truck will start if you jump the starter, however the transmission will not engage. The "DRN" (Drive, Reverse, Neutral) only flashes when pressed. I believe the low voltage crank corrupted a module or fried a module, therefor the truck does not know it is in Neutral, therefore it will not crank with the key. I had the truck towed to International. I gave detailed notes of what was going on, however the tech never read them, therefore, spending 3 hours and coming up with a bad starter.........No, it's not the starter, it starts if you add 12 volts to the solenoid, and the transmission doesn't engage or read......After updating him, he says there is not any communication with the TCM. They want another 4 hours to check power and grounds before replacing the TCM. They say there is only 1 TCM in the world and it's in Canada at $5,000 plus $200 for shipping + install and programming and is 2 weeks out. Whoooo Saaaawwww!!!! Question is: Do you think that the TCM itself is fried, electrical issue in the wiring/connections, or is there something else to have checked? Thank you in advance!!!!
Also, The dealer was able to find someone to build out a new TCM, however they want 8 hours to R&R the TCM. Does this sound right? From what I see the TCM is just on the side of the trans with a few bolts and 2 connectors. Thanks!

 

I would suspect that you have a connection problem in the
battery power or grounds causing the slow cranking. The
body controller needs to see a neutral signal or it will not
send power to the starter relay. There should be a fuse in
the battery box for the TCM. Make sure it has not blown.

 

The slow cranking was from bad batteries. They were changed out. There is not any cranking now, and yes you are correct the neutral signal is not being received to the starter relay. The dealership says the TCM is not communicating. I hate to spend the money on a new TCM if its the BCM or something else. All of the fuses in the battery box are good.

 

There is a low voltage disconnect system on this truck- it shuts everything down.
Disconnect all the batteries and let it sit for a while. Reconnect but make sure all batteries are charged up fully. I’d also recommend getting a continuous 4post negative and positive cable - not the individual straps you have. There is a 100 amp fuse - take that out and clean it - make sure all the connections are clean and the ground strap connection is also clean and tight. If you have a battery disconnect- check that also.
Basically strip the entire wiring down and cleaning each and every connector- even if it looks good. The circuit behind the instrument cluster sends the signal to the starter I’ve heard that if you disconnect the battery for an extended time, it messes up the ecm. Old wives tale.
But then you have an International- so anything’s possible!! Just kidding

 

I have disconnected all batteries multiple times to try to reset everything, it has not helped. All cables were cleaned when the new batteries were installed. The 125amp fuse was good at the battery along with the other smaller fuses. I would think that the dealership would be able to pin point the problem with their scanner and software, but they are spending hours looking in the wrong places. They say there is not any communication with the TCM and they want to replace it, but if they are wrong guess who has to float the bill? I am trying to get suggestions that are cheaper and easier to look at rather than replacing the TCM. They also want to charge me 8 hours of labor to R&R the TCM, which seems about 7 hours too many to me. They have not ordered the new TCM yet, I was hoping to get an idea here that we haven't tried yet. Any and all ideas are welcome!!! Thanks!

 

You did not miss a wire on one of the batteries or get one on the wrong post?

 

It’s going to be something real simple. If you have a power probe iii - start troubleshooting with that. I’m shooting in the dark - try grounding with the probe iii and see if it starts -check all grounds - add a new ground- if you bypass and start it directly the bcm will not necessarily communicate with the Tcm. I doubt if it’s the ecm or the bcm. It’s an electrical issue. You just have to literally do this one step at a time. Start with the battery isolator if you have one - check each cable. Any mechanic with some experience in circuits should be able to pin point this. Insite program is not going to help troubleshoot an electrical issue.

 

There is a crank inhibit relay that the transmission is responsible for triggering to allow it to crank. If the tcu is not coming on line, then that relay will not trigger. You can jump the relay to make sure your starter is good, the engine will run, but you will get the no communication with the tcu. Low voltage cranking will take out an Eaton TCU. We have see this a few times. The TCU are mounted on the side of the trans, but it is tight in there and access is limited. If you don't like their labor quote and think it is easy, then replace it your self, simple as that.

 

Thank you for the helpful information Heavyd. It would be nice if the dealer could relay the information that you just did. I have seen many of your post replies and am confident that you know your ####. As for their labor quote, this particular dealer has overcharged me before on labor and it seemed as if they were trying to do it again. I had spoken with the tech that was working on my truck and he had told me that it would be 1-2 hours to change out the TCM, so when the service writer said 8 hours, it didn't match up. According to the tech after speaking with him again, he said that he didn't realize the TCM was as hard to get to as he had originally thought. I have no problem paying for work, but I also do not like being taken for, which is why I asked how long you think it would take. The new TCU was ordered on Friday and is supposed to be at the dealer on Wednesday this week. Hoping that it will fix the problem and have an update Wednesday or Thursday. Thanks again, I do feel more confident that we are replacing the correct part. It's a $7,000 quote so far, so I was a little nervous.

 

How old is the starter? Even though it would not matter now, since it has probably burnt connections inside after trying so hard to turn with low voltage.

JFTI: I have an old used truck I had a pleasure to acquire awhile ago, and no matter the batteries, it would crank slow causing overload. Replaced batteries, thought they are bad, cleaned everything, same thing. I figured it after the starter just died and I've had replaced it. Turns like a champ with same batteries there after. Sorry for your troubles though, hope that chip on the tranny will do the trick.