I had an emissions-related repair last week. Nox was outside range. They fixed it and I saw the data myself. They forced a regen to clear the codes. The "permanent DTC" code came back. From what I've read, there's a specific sequence of events, including a "drive cycle" , possibly called a UTDP or " Universal Trip Drive Pattern" that must be performed in order to clear permanent DTCs. This may be truck specific and seems to be a big secret, although mechanics must all do it to clear emissions-related codes. I can clear codes and force a regen but how do I discover the drive-pattern sequence for my 2013 Cascadia? Thanks
do back to back two regens to clear emission codes. Some emission codes can be cleared without regen and some codes can be cleared by one time regen. Just follow instruction for specific code(how to fix it and clear it).
When it only says “Permanent” that’s just saying it’s been stored in the MCM basicly a “time stamp”, so that if the repair didn’t hold, it can through the Government code faster..... it’s not like the “self healing”. Where if the check engine light and MIL light are on. If the conditions setting the Check code are removed and the Check light goes off, the MIL will stay on for the next three trips. If that’s what your looking for. Detroit considers a trip : Engine Start, vehicle Drive Over 30mph and more than a mile. Vehicle stop engine shut down.
