Keith Browning Posted September 4, 2015 Share Posted September 4, 2015 I am working with a 2012 F550 that is a municipal dump truck - spends most of its time idling and putting around town. Originally came in for heavy ammonia smell that made workers sick, check engine light and so on. I replaced the faulty NOx sensor and it cleared up. It has returned again with a P207F for reductant performance. I went through the pinpoint tests (because I have already exhausted the TSB options and it passes all testing... which leads you into that vicious back and forth cycle between two tests. I stopped. Since I already had the reductant injector off for the dosing test I grabbed a boreoscope and had me a look. The SCR was totally white and I don't know how it wasn't clogged but... I ran it past the Hot Line. To clear that you run a manual regen three times in succession. It was recommended that I replace the NOx sensor again as well, reset all of the SCR tables and re-evaluate. Quote Link to comment Share on other sites More sharing options...
lmorris Posted September 4, 2015 Share Posted September 4, 2015 They make you run the three regens and borescope it now when getting prior approval for a new SCR if the tailpipe is clean. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 4, 2015 Share Posted September 4, 2015 Nice! Good information here. I've been lucky and haven't ran into any SCR related issues that weren't easily fixed. I've been putting off the borescope investment but I guess it's time. Quote Link to comment Share on other sites More sharing options...
amailloux Posted September 5, 2015 Share Posted September 5, 2015 We have some dmax ambulances that set p207 after extended idle time. I was told by GM that it is due to Def crystalizatoon and no fix is available. I usually enable a regen and drive about 30 miles and the scr starts reducing better than 90% Quote Link to comment Share on other sites More sharing options...
2006 Posted September 6, 2015 Share Posted September 6, 2015 I had the same code/problem a while back under warranty. A new SCR fixed it. This may sound stupid, but why can't you unbolt the rear of the scr and spray straight water in the def injector port? Wouldn't this clear out all the def crystals? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 7, 2015 Author Share Posted September 7, 2015 I had the same code/problem a while back under warranty. A new SCR fixed it. This may sound stupid, but why can't you unbolt the rear of the scr and spray straight water in the def injector port? Wouldn't this clear out all the def crystals?Did you contact the Hot Line? They seemed pretty confident the three manual regens would clean it. I did not bother to pull the injector back off and take a peek with the boreoscope (flat rate you know) When I first contacted them my question was if there were any way to clean the crystals out. Washing was never mentioned. My thoughts are that the regens are safe and probably effective - or they might have wanted me to try this before condemning the filter assembly. If the truck comes back soon we will know. This time I drove it, a valet drove it and my manager drove it to put some hard miles on it. Quote Link to comment Share on other sites More sharing options...
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