How to clear the SCR closed loop at maximum limit SPN 520372 FMI 16 fault code. If this fault code is ignored long enough it will trigger

DEF inducement DEF lamp active SPN 521049 FMI 31

DEF inducement CEL lamp active SPN 521052 FMI 31

Then eventually the truck will derate.

To clear the fault codes, simply hitting the clear fault codes will NOT work. You have to check all the fault codes and fix them accordingly. Then you will need to check the following:

1. DEF quantity check
2. DEF ADS self check and look at the RPM speed
3. Check the delta pressure sensor, diesel doser injector and signs of blockage,
4. Perform a successful parked regen, if all goes well and passes
5. Perform an SCR efficiency test immediately after and monitor the LARMF compensation. The number must be at 0.91 or higher. This is pass or fail and must run completely without any interruptions.