Mack Technician Posted June 18, 2020 Share Posted June 18, 2020 I found the software in the VOE Volvo ACM's will accept infinite zero as a plausible, real time, parameter reading. When you access your Tech Tool you'll see one of 2 readings for "NOx after SCR", it will be a zero or a dash. 0 or -. This point applies to a machine that reads "0" (zero) with the engine off & key on. If your having a freak out in your emissions system you can take out the downstream NOx sensor and zip tie it into fresh air. I intentionally ran a unit cold so the downstream NOx sensor never got hot enough to activate, self incriminating, its a tattle tail sensor that accepts zero NOx as plausible. Did it for almost an hour. After reset it stays out of derate and won't code regardless of "NOx Before SCR". So if you need to get the unit to run till the end of day...….you can run through it, possibly indefinitely, by breathing the downstream sensor. No derates. Not sure what it may do during regen, but by then you'd have a solution and reinstall it. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/ Share on other sites More sharing options...
fjh Posted June 18, 2020 Share Posted June 18, 2020 Good info bro keep up the good work! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-453653 Share on other sites More sharing options...
Nobody454 Posted June 18, 2020 Share Posted June 18, 2020 i heard you can disconnect the speed sensor? so it thinks youre not going fast enough to make it derate? not sure if thats real or not Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-453655 Share on other sites More sharing options...
Mack Technician Posted June 19, 2020 Author Share Posted June 19, 2020 2 hours ago, fjh said: Good info bro keep up the good work! I have the guy on my text. We’re in the 12th hour and no derate or faults 😆 . If your stuck waiting on replacement parts the damn thing lets you own it with a 7/8” wrench and one stainless zip tie. Pretty funny, they may use dime store sensors and dime store wiring, but thank goodness it’s dime store software logic!!!! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-453668 Share on other sites More sharing options...
fjh Posted June 19, 2020 Share Posted June 19, 2020 Yup definitely worth trying if your stuck. An yup thspeed sensor thing apply to standard only transmission! Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-453686 Share on other sites More sharing options...
Mackpro Posted July 22, 2020 Share Posted July 22, 2020 Any word on removing the outlet NOX sensor to fresh air as a more permanent fix ? Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456361 Share on other sites More sharing options...
Mack Technician Posted July 22, 2020 Author Share Posted July 22, 2020 19 hours ago, Mackpro said: Any word on removing the outlet NOX sensor to fresh air as a more permanent fix ? No, it got me through two shifts though. I reset the eventual code then ran it for a while with the NOx sensor installed. When it "DEF quality" coded on me a second time I removed the sensor to fresh air again and ran it. The second time it was as if the machine had artificial intelligence for learning the cheat, within the hour it was down for NOx code. Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456413 Share on other sites More sharing options...
Mackpro Posted July 24, 2020 Share Posted July 24, 2020 I got a 2011 non-OBD that’s needing a DEF doser and outlet NOX sensor. But I’m unable to do any work on it till Monday . I pulled the outlet NOX sensor out into clean air and cleared codes and did a learned data reset and turned it loose for a couple of short trips till I can get back on it Monday. Hopefully it will make it Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456535 Share on other sites More sharing options...
Mack Technician Posted July 24, 2020 Author Share Posted July 24, 2020 (edited) 8 hours ago, Mackpro said: I got a 2011 non-OBD that’s needing a DEF doser and outlet NOX sensor. But I’m unable to do any work on it till Monday . I pulled the outlet NOX sensor out into clean air and cleared codes and did a learned data reset and turned it loose for a couple of short trips till I can get back on it Monday. Hopefully it will make it Thanks I’m curious to know how the story ends? I also theorized, on the off-road, that the operator could take the “open to fresh air NOx sensor” machine down every 15 minutes for 30 seconds of key off. The machine will not logically determine a sensor issue....is the thought. It’ll think he’s running short cycles and not heating the NOx sensor enough to activate it. I putz around the yard for a long time to finally get the downstream heated to the point of registering. Meanwhile, the DEF process defaults to a sleep mode of 6PSI air delivery to nozzle instead of typical 20-22 PSI because it doesn’t have its downstream NOx reading for regulation of delivery. It (software) seem to expect to hold that cool-sensor-sleep-mode for a long time without reacting with a fault code. 🍀 Good Luck Remember the good’ol days when we just fixed machines instead of playing mental chess games with their logic? Edited July 24, 2020 by Mack Technician 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456542 Share on other sites More sharing options...
fjh Posted July 24, 2020 Share Posted July 24, 2020 2 hours ago, Mack Technician said: Thanks I’m curious to know how the story ends? I also theorized, on the off-road, that the operator could take the “open to fresh air NOx sensor” machine down every 15 minutes for 30 seconds of key off. The machine will not logically determine a sensor issue....is the thought. It’ll think he’s running short cycles and not heating the NOx sensor enough to activate it. I putz around the yard for a long time to finally get the downstream heated to the point of registering. Meanwhile, the DEF process defaults to a sleep mode of 6PSI air delivery to nozzle instead of typical 20-22 PSI because it doesn’t have its downstream NOx reading for regulation of delivery. It (software) seem to expect to hold that cool-sensor-sleep-mode for a long time without reacting with a fault code. 🍀 Good Luck Remember the good’ol days when we just fixed machines instead of playing mental chess games with their logic? Yup Hide And go Seek! Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456571 Share on other sites More sharing options...
Macktech20 Posted July 27, 2020 Share Posted July 27, 2020 Unplug the speedo sensor on the back of the trans Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456781 Share on other sites More sharing options...
Popular Post Mackpro Posted July 28, 2020 Popular Post Share Posted July 28, 2020 Truck returned tonight for me to install the new parts on . Truck was driven almost 800 miles pulling a loaded dump trailer .with the outlet NOX sensor sending unit unscrewed from the exhaust pipe and just zip tied up handing in fresh air. I plugged up tech tool to check codes and only one fault code . It was inactive and was for the outlet NoX sensor , the FMI was 7 I believe, unidentifiable failure. No derate or other warnings of any kind. Looks like the trick worked . Not sure if it will work on any of the 2013 emissions OBD trucks . 1 2 Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-456918 Share on other sites More sharing options...
Mack Technician Posted July 29, 2020 Author Share Posted July 29, 2020 OH ho-ho YES my FRIENDS !! A chink in the armor and it was soooo stupid simple. Good job team . Try it on a late model someday. The VOE OBD wouldn't have it, but it bought me some time. Times valuable if 60% of the loader fleet is flat-lined and production calls on the Red Phone to ask "what the %#@% is going on out there!!!". 1 Quote Link to comment https://www.bigmacktrucks.com/topic/62965-emissions-system-get-home-trick/#findComment-457075 Share on other sites More sharing options...
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