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Diagnosing P206A Malfunction in urea quality sensor

moocowman

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2013 Hino 338. DCU shows P206A malfunction in urea quality sensor. Also has P2045 urea tank temperature sensor 2 (hi). I know I need to replace the tank temperature sensor, but there's no such thing as a urea quality sensor on these trucks is there? Is it just making a guess based on some bad NOx readings?
 

Hino123

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2014 The def quality sensor was installed in the def tank with the sending unit. 2011-2013 use the nox sensors to validate def quality. Check the yellow def pump connector for def leakage. Its not uncommon to have the pump crack internally and wick def into the harness. I would check th4 sensing unit also but if you are replacing it just make sure no DEFC gets on the connectors.
 
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moocowman

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Thanks for the reply. I will check the connector. ..."check th4 sensing unit".. You mean check the sending unit? What would I be looking for in the sending unit, a leak at the connector as well? Yes, I'll be replacing it because of the temperature sensor fault, but for future reference, what could go wrong with the sending unit to cause P206A?
 

Hino123

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DEF wicking in the harness from the def pump and contaminating the sending unit/level sender (def quality sensor 14my up)
 

FloraJay

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Hi..reductant quality should be determined by the nox12 sensor. one would assume that the code sets due to either poor reductant quality, scr condition, nox sensor, nox module, def injector. regardless, yes, it is a def system issue
 

moocowman

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Is there a test that can be commanded to dispense DEF to check the spray pattern and volume of DEF dispensed? I do this on Cummins and Fords, but don't see a similar test for Hino.
 
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