CCMtruck Posted January 20, 2020 Share Posted January 20, 2020 I've got the dreaded 4094 fmi 1 code. Checked def pump pressure, quality and quantity of fluid. Removed def nozzle to checked spray and measured fluid. Did find several boost leaks that i repaired. Performed scr crystal sublimation test and then a regular regen test and the code is still active. During regens the inlet nox sensor never changed and always read 0 and the outlet nox sensor read correctly. Checked both NOx sensors and are the latest part numbers. Checked ecm and acm software and is up to date. Took unit on road test while monitoring and inlet nox sensor still never read off of 0. Any thoughts? Quote Link to comment https://www.bigmacktrucks.com/topic/60638-spn-4094-fmi-1/ Share on other sites More sharing options...
CCMtruck Posted January 20, 2020 Author Share Posted January 20, 2020 Another question. During the scr crystal sublimation test the def pump pressure was dropping as far as 109 psi. Shouldn't it stay around !30 psi? Quote Link to comment https://www.bigmacktrucks.com/topic/60638-spn-4094-fmi-1/#findComment-440978 Share on other sites More sharing options...
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