Having issue with freight liner in shop. What should I do next

I'm so glad I just stayed with a Manual even though everybody was telling me how great, and trouble free the D12 is.

 

What type of transmission, is it an Ultrashift plus? If it's a hybrid trans I don't see why they are asking the engine maker Detroit. You need to go there and talk to the service manager in person.

 

used to Holt truck center in irving had a guy good with those transmissions issues.
Tell them to fix it, or you having it taken to a shop that knows how to fix a problem without creating another, then guy taking off leaving it in pieces.
I’d call holt , and explain what’s going on

They’re over by big Ds travel center

 

Well, I don't know about that. I will tell you if you think you're going to sell that one and just go out the next day and by one with a manual, they are very hard to find and are little more money, for that reason.

 

A Freightliner with a DT12 has about 19 different computer controllers in it. Almost 50 percent of electrical glitches can be solved by doing one thing.

When you go to start the truck from the key off position, turn the key to the ON position, and WAIT.

30 seconds or so watching the gauges cycle, all the idiot lamps go off, then crank the truck.

All the computers need 30 secs to power up, read all the sensors are working, communicate with each other and not throw a code.

I had a 2020 that did the exact thing the OP stated. Disconnecting the batteries for 5 minutes cleared the code and unlocked the shifter. I was treating the truck like a car and just turning the key to start.

 

I had to pass Houston today around 5 pm, driving on I10 and going east. It wasn't fun, but D12 made it much easier.

 

I took my truck there when I was new and worked for Prime. Those thieves at that shop put in a new computer, did thousands of dollars of unnecessary work, took days....
When they finished I didn't make it far before the same problem popped back up. Drove it up to MO and took it to their Freightlinrr shop, it was a simple wheel speed sensor the entire time. Moral of the story is that that place scams ignorant customers. Good luck.

 

My Amish neighbors always glad that they're stayed with horses)