Cummins with codes that will not clear
I went to a shop last week to look at this truck, two codes were in the PCM and would not clear. The shop diagnosed the truck with a bad particulate sensor. The sensor was replaced and the code did not come back. The 3712 and 3714 codes however would not clear, and the engine was in derate mode. Below you can see the conditions for clearing the code:
3712 - Aftertreatment SCR Operator Inducement- Data Valid but Above Normal Operational Range- Most Severe Level
Conditions for Clearing the Fault Code This fault code will go inactive once all other active fault codes have been addressed. Refer to the appropriate fault code troubleshooting tree. The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and passes.
3714 - Engine Protection Torque Derate- Condition Exists
Conditions for Clearing the Fault Code This fault code will go inactive once all other active fault codes have been addressed. Refer to the appropriate fault code troubleshooting tree. The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
A regen and SCR test was performed post repair. All of the temps looked perfect and it passed all of the tests. The 3712 and 3714 still would not go away, there were absolutely no other codes. I have experienced this before, my simple minded explanation is that the codes are latched and there is a software issue. I decided to reflash the computer to the latest calibration. The codes were gone and everything was back to normal. If a reflash was not available, I would have still flashed the computer like an install and that would probably have the same effect. None of the calibrations cited this as an issue, so it was just a matter of uninstalling and reinstalling software, just like a PC or phone. I hope this helps someone out someday.
Matthew based on my experience after running the scr test the codes should go from active to inactive after an extended idle for a minute or two once it goes inactive then you can clear the codes. The scr test has to pass of course.
I did the test and it passed, no luck on this truck.
I also have had one where i reflashed the ecm with the same cal file and it fixed it. It seems like the software gets corrupted and wont budge on a code clear
That's interesting, thanks for sharing. Sometimes I have had the same issue. Most of the time though after I have the vehicle up to operating temp I clear all the codes and it goes away.