fracroy Posted December 29, 2013 Share Posted December 29, 2013 SCR derate keeps returning even after crystal sublimation and regen NOx sensor codes even after replacing and reagent dosing valve code using tech tool vcads pro guided diagnostics several 2012 mack in my fleet mack house backed up for months help please some one really familiar with program much appreciated! Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/ Share on other sites More sharing options...
Challenger Posted December 30, 2013 Share Posted December 30, 2013 Give all your codes exactly how Guided Diagnostic gives them. What exactly have you replaced? I've seen alot of fleets with dirty DEF fluid. I've also seen DEF dosers leaking. Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-223953 Share on other sites More sharing options...
Challenger Posted December 31, 2013 Share Posted December 31, 2013 What truck?What engine? Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-223961 Share on other sites More sharing options...
Mackpro Posted December 31, 2013 Share Posted December 31, 2013 90% of the time we find that the NOX sensors are the problem, They have new upgraded ones, we replaced a ton of them. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-224042 Share on other sites More sharing options...
fracroy Posted December 31, 2013 Author Share Posted December 31, 2013 Mp8 2012 mack chu613 replaced NOx sensors ran guided diagnostics dosing test ml measured were spot on Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-224153 Share on other sites More sharing options...
fracroy Posted December 31, 2013 Author Share Posted December 31, 2013 Pinnacle Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-224155 Share on other sites More sharing options...
Challenger Posted January 1, 2014 Share Posted January 1, 2014 What are the codes you're getting from Guided Diagnostics? Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-224363 Share on other sites More sharing options...
Mackpro Posted January 2, 2014 Share Posted January 2, 2014 On a few truck trucks, even after replacing both nox sensors and doing 2 back to back regens and watching the NOX levels drop, the codes still show active. We have been able to then clear the codes and do 3 short test drives and codes never comee back. Mack had a SPN-5394 FMI-17 / SPN-4094 FMI-18 check sheet but its not on the Mack dealerportal anymore, they say they put the steps in Guided Diagnostics Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-224478 Share on other sites More sharing options...
moonsetter Posted January 21, 2014 Share Posted January 21, 2014 how do you force a regen on ur truck? Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-227871 Share on other sites More sharing options...
j_martell Posted January 22, 2014 Share Posted January 22, 2014 Blue switch, top row, 2nd from the left. Down is off, middle. is auto, up is forced. 125000km (no idea on hrs....should check) on my 2011 MP7 and only twice has it told me to regen Quote Lack of planning on your part does not constitute an emergency on my part.... Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-228008 Share on other sites More sharing options...
Kyle 537 Posted January 22, 2014 Share Posted January 22, 2014 Have you ran the scr system test. To be sure the def pump is workin right? Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-228035 Share on other sites More sharing options...
Kyle 537 Posted January 22, 2014 Share Posted January 22, 2014 I see, you did. Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/34055-scr-problem/#findComment-228037 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.