Help! Engine derated to 25% and won’t start!

[Tino C]

I’ve just purchased a 2014 Kenworth T660, ISX 450ST CM2350 with a bit over 450,000 miles on it. After running the first 1000 miles without issues I did something stupid and let my DEF level low until the low level light came on. Closest truck stop was 35 miles away and right before taking the exit the amber check engine light came on and I immediately noticed the lost in power. After refilling the DEF tank it kept doing the same. I managed to get home since I was only 30 miles away( it would only let run 55 mph). The engine derated to 25% percent came on as I was parking. Next day I had my local shop guy take a look at it and he couldn’t get rid of the active code 3714. The truck won’t start.


P.S. Please keep in mind this is my first emissions Truck. I had only had Carterpillars before this one. Any help as to how to proceed is much appreciated. Drive safe and Merry Christmas to y’all from Houston, TX.      

[imalumberjack]

I googled it sooo this is not from experience, its what I found online and seems reasonable.
1761 seems to be ; DEF tank level sensor circuit sensor failed (high). Did you disconnect the sensor? and forget to put it back?

I do not think it would prevent truck from starting? You might want to change DEF filter while your working on it ....if you ran tank dry? everything in there went into filter.

The reason I did not address other codes as they are somewhat irrelevant, often with these engines they will give you info but you need to fix one or two and they allow the rest to be cleared.

[Lonestar10]

always keep def full stop for fuel stop for def the longer the DEF tank is below full the more time crystals have to form in the tank which can cause anything that moves to become stuck and anything that filters to become plugged.

DEF is nasty in non liquid form as basically its water and nitrogen fertilizer mixed together same exact thing ethanol plants do mix nitrogen "UREA" and water and send it to the fermentation tanks to give the yeast nitrogen to help break down sugars to ethanol. just DEF is filtered of dirt and waterborn contaminates.

[Signature620]

Did he clear other faults before this photo was taken? That fault 3714 is just an information fault to say that there is a derate active due to emission related faults.

Does it not fire or not turn over?

[Tino C]

(12-24-2018 )imalumberjack Wrote:  I googled it sooo this is not from experience, its what I found online and seems reasonable.
1761 seems to be ; DEF tank level sensor circuit sensor failed (high). Did you disconnect the sensor? and forget to put it back?

I do not think it would prevent truck from starting? You might want to change DEF filter while your working on it ....if you ran tank dry? everything in there went into filter.

The reason I did not address other codes as they are somewhat irrelevant, often with these engines they will give you info but you need to fix one or two and they allow the rest to be cleared.

I didn’t disconnect the sensor but, the I did run the tank dry.. The guy from my local shop told me the same about how it should not prevent it from starting. I will take to the shop on Wednesday after the holidays.Wherever it turns out to be I will definitely replace the DEF filter. Thank you for your response.

[Tino C]

(12-24-2018 )Signature620 Wrote:  Did he clear other faults before this photo was taken? That fault 3714 is just an information fault to say that there is a derate active due to emission related faults.

Does it not fire or not turn over?

He did clear the other inactive faults. I will have them look into it to see if those faults can be still found but I think it was the one showing “low DEF level”. It does not turn over. Thanks for taking the time to respond!

[Tino C]

(12-24-2018 )Lonestar10 Wrote:  always keep def full stop for fuel stop for def the longer the DEF tank is below full the more time crystals have to form in the tank which can cause anything that moves to become stuck and anything that filters to become plugged.

DEF is nasty in non liquid form as basically its water and nitrogen fertilizer mixed together same exact thing ethanol plants do mix nitrogen "UREA" and water and send it to the fermentation tanks to give the yeast nitrogen to help break down sugars to ethanol. just DEF is filtered of dirt and waterborn contaminates.

I’ve been absorbing all the information I can get online regarding After Treatment systems. Thanks for the input!

[Signature620]

Some of these aftertreatment faults have a hard time resetting themselves. You could try re-calibrating the ECM. After that you can chase the "no cranking" complaint. Make sure keyswitch voltage is going to the starter, make sure the ecm operating state isn't showing something like 'starter lockout', see if the ECM throws any faults after a reflash.

[imalumberjack]

I would find the DEF level sensor (its on or in DEF tank) pull it and clean it or replace it, it should clear codes. With DEF level sensor not working the truck computer does not know you filled the DEF tank, it still sees it as empty.