Cummins isx with code 3232 and 3574; going active and inactive

[imalumberjack]

Have you replaced the DEF filter? It seems to me once you start having problems its time to go through and clean and replace ALL sensors on aftertreatment. Have you tried the DESA program? it runs the engine through a series and gives you a report. There is a campaign on some of these engines as far as the scr being faulty, you can check on cummins quick serve.