"Stop Safely Now" message.

I have a friend stranded at the moment when his '08 had the "stop safely now" message come up and the truck shut off. Won't restart after clearing codes. Has a SCT tuner with Erics tunes. Code u2023 popped up. Nothing else. Any idea how to get this thing running again?

Thanks in advance

Have tried returning to stock as well as changing tunes.

That is a communication code. It doesn't show up in my PDF file so I don't know what the description of it is.

Communication error between modules is what I came up with. Truck ended up restarting and he got home. But still curious what it was and how to prevent it from happening again.

maybe a loose sensor on the exhaust/delete pipe?

I wouldn't think so. I don't think that would result in a communication code. Something could be up with the PCM or TCM. It could have also been a freak thing and may never show up again.

What codes or issues would create this message? Happened again to said truck.

And I should mention nothing was done since last time. Drove fine for a month or so.

Start checking wires on the ECM/TCM. Something is lose

After an hour it starts up and runs fine. I plan on checking all connections. I thought it was mainly the DPF sensors that would cause that message to appear and disable the truck?

Does the truck still have a DPF on it?

No. But the sensors are in the delete pipe. Truck was in Erics 300 tune at the time.

Truck is in what's called "Failure Management Effect Mode"

Will not crank/start with the key for 1hr from time of failure.

Suspect last EGT sensor in the delete pipe. Manually jumping the starter either at the starter or at the breakout near the right hand battery will allow the truck to crank.

I was having him monitor all 3 of the sensors and the last one does seem to be out of whack. So hope that is the case.

Thanks