95% of our heavy equipment issues stem from either DEF or Regen issues. Speaking of, bragged on the old truck a bit too much last month. For the first time ever, 15 fucking years, had an issue with the DPF. CEL came on but my scanner wouldn't read it. Ended up being the rear EGT sensor for the DPF. It wasn't reading, so it wouldn't regen, so it plugged. I was towing the travel trailer home from the hill country. Luckily enough, I had my scanner with me and I just had to keep resetting it every 5 mins or so when it would try to throw it to limp. Ended up the sensor was fine, but it wouldn't get voltage to it. It needs some funky 4.5v. I tried to jump it off the front sensor that also takes 4.5, but couldn't get it to work. When I bought that truck 15 years ago, I told myself I'd delete it if the DPF ever fucked up, in lieu of replacing it. SO, there's a 4" straight pipe in the garage, the exhaust is pulled off. DSP5 switch installed, and my Autocal EFI live shows up tomorrow. 10, 30, 60, 90, and 150 hp tunes. Not crazy about how loud its going to be, but no fucking way I'm paying that much to get it fixed back to stock. Was half the price to pipe and tune it.