Guess I am officially the guinea pig, so I wanted to share with the forum my experience with the above. Like many of you, I have lived with angst about DEF sensor failure, so I thought Iíd share my experience in the hope that it would help others worried about or experiencing the same.
On Sept. 12, 2021 I was alerted by the IRV2 forum regarding the existence of a Diesel exhaust fluid Sensor Simulator (DSS) that would allow one to temporarily bypass a defective DEF sensor and allow one to proceed to a service center avoiding a dangerous roadside situation and/or costly tow (links below). I thought that such a device might be an inexpensive insurance policy in the event of a DEF sensor failure, so I purchased the parts ($78), programed the board and assembled. Programing was much easier than I anticipated, but fashioning the cable was the tough part (tight wiring inside of a small DB9 connector). The completed device was ready on Sept. 17th, but little did I know that I was going to need the dang thing soon.
Less than 48 hours later on Sept. 19th, DEF sensor failure occurred on my 2017 DSDP 4369 on Spartan K2. This was a real shock as I had babied my DEF system filling it at every fuel fill, etc. for the last 2 years, and at the time, the DEF tank was >3/4 full. Initially the MIL, CHECK ENGINE and a solid DEF lamp came on, and fault codes 3364 DEF QUAL, 1761 DEF VOL, and 3031 DEF TEMP were observed. Shortly thereafter (15-20 min/miles of driving) fault codes 5842 SRC MON and 1569 TOR DER were also generated. Clear 25% derate was observed at the same time via my connected ScanGaugeD looking at horsepower output (typically reached 360 hp at full throttle now 265 hp). Finding a safe place to park, allow the engine bay to cool and my nerves to chill, I powered down the chassis, disconnected the DEF sensor from the chassis harness, and plugged in the DSS (anchoring it securely via zip ties). After re-powering the chassis and starting the diesel, the CHECK ENGINE and DEF lamps disappeared, but the MIL light remained. All 5 of the codes still registered in the dash system as well as the ScanGaugeD, so I used the ScanGuage to to clear. All codes cleared except 3031 DEF TEMP. I then drove the coach and verified no additional codes appeared and normal horsepower returned as well. At my next stop, I shut down the engine and restarted. This last operation cleared the final 3031 fault code.
The next, very important step was to arrange a proper, permanent repair to this temporary DSS fix. Therefore on Sept. 20th, Spartan was called, and they verified the issue as a failed DEF sensor. To my amazement, they had the part and were willing to overnight, CoachNet arranged a mobile service visit to my location, and Cummins Sales and Service in Indianapolis did the actual work in the field.
A huge thank you (acknowledgements below) to all involved that helped me deal with my DEF sensor problem in a super timely manner! I have numerous pictures that I will post soon. PM me if you have questions.
Letís get out there RVíing again with confidence!
DSS and Carry On!
~ Mark, Vic, Rob, and others (DSS Development Team). Empowered me to temporarily fix in the field. Truly a fun experience building, programming, and deploying the DSS. I say ďDSS and carry onĒ t-shirts/hats should be made!
~ Dave, Spartan. Had the part and was super flexible in how to address issue and ship.
~ Jacob, CoachNet. Owned my problem, and worked with Laura at Cummins and Dave at Spartan to expedite.
~ Laura, Cummins Sales and Service, Field Operations Office, Indpls. Was willing to go the extra mile to jump through hoops at Spartan and CoachNet and arrange for someone to get to my location quickly.
~ Rob, Cummins Field Service Tech. Awesome repair! What a gentleman!
Original article describing the DSS: https://www.rvtravel.com/def-sensor-...und-rvt-1017b/
DSS Build (Uno R2 ATMega256o version - parts for Arduino Due unavailable): https://defsim.myervin.com/using-an-...-def-simulator