Hi guys. I'm new to here but have found some good info so thanks for that. So I have a 2011 IC CE300 with DT MAXX. It died in route and wouldn't start again. The engine is getting all the pertinent info it needs to run (key on jump the starter it starts and runs fine), but the multi-plexer isn't communicating with the trans. So it won't tell the starter to go because it can't tell that its in neutral. I have checked all the relays and fuses that I know about. We do not have any info on this ONE bus in our fleet of 50. I have checked the wiring at the TCM and ECM but I'm unfamiliar with which pins should be powered up/ground. So for now just checked for bent or broken or corroded pins. Found none. I checked the wires out of the battery box and up to the firewall bulkhead and found nothing unusual. The dash just says " ELECTRIC FAULT". So if you have a schematic or some advice, I'm all ears. Thanks in advance.
If the bus starts and runs fine after jumping the starter then you may have a bad wire from the ignition switch to the starter relay. Assuming you've tried changing the starter relay. I've come across that before and replaced that wire. Not sure why it died on you though, could be CMP or CKP sensor. Hope this helps.
Sounds like a TCM to me. If it has the heat sinks that are round as opposed to fins it's probably shot. I have 80 of these so swapping one is an easy verification. They fail often enough I keep a pre-programmed one on the shelf. There are a couple of power and ground pins on the chassis side of the TCM connector that Allison has you check.