SCR/DOC leaking DEF (Cummins ISX15)

Heavyd · Nov 24, 2017

Can you tell how or why it failed and leaked? Did it rub through on something or tied too tight?

Jsnell510 · Jul 6, 2018

RomanSGI said: ↑

Forgot to update you guys. It was the DEF hose. It runs from the DEF Tank to the Def Dozer. It was exprensive $325 at my local Kenworth dealer. Much cheaper online but I couldn't wait for it to come in the mail (it would result in more down time). So it was a pain in the *** to install. I found it easer to access to remove the driver side fairings (easier to get under the truck), and then there's a black panel behind/under the DEF tank where you attach the other end of this hose. You have to remove the bolts off of that to access where it attach/detaches.

A BIG THANK YOU to ya'll for your replies! @Justrucking2 @Goodysnap @Heavyd
Click to expand...

Wat was the part #

Mykim Transport · Jan 23, 2019

RomanSGI said: ↑

After replacing Exhaust Pressure Sensor and Sensing tube which is located on the front right of the engine. I ran a Regen with Cummins INSITE. After about an hour into the regen, the SCR/DOC started leaking DEF Fluid and formed a huge puddle. After the regen was over. It stopped leaking.

The gauge inside the truck showed I went from 3/4 to 1/2 tank of DEF. So I drove about 20 miles to a truck stop, topped off the DEF tank, after fueling pulled forward out of the line and went inside truck stop to grab a bite to eat. When I came back to the truck. AGAIN, def puddle on the bottom. The DEF gauge showed it went from FULL Tank to 3/4 tank. I pulled out and parked in a parking spot. All the way to the spot it was leaking fluid. I then hopped on the highway and drove about 20 miles back to my yard. When I got to the yard, the DEF Fluid was no longer leaking. And DEF gauage read it still had 3/4 DEF.

The engine is derated. I connected INSITE, and it's showing the following codes:

3574- Aftertreatment 1 Diesel Exhaust Fluid Pressure Sensor-Data valid but below normal operating range.

1682- Aftertreatment 1 Diesel Exhaust Fluid Dosing Unit Input Lines-Condition Exists

It was too dark last night. And it was really late. I'm thinking it's some type of DEF Lines that carry the fluid, maybe? Anyone else had this issue in the past. I will upload a short video clip on youtube and post the link here in a few minutes.

BTW, this is a 2012 kenworth t660.
Click to expand...

RomanSGI said: ↑

After replacing Exhaust Pressure Sensor and Sensing tube which is located on the front right of the engine. I ran a Regen with Cummins INSITE. After about an hour into the regen, the SCR/DOC started leaking DEF Fluid and formed a huge puddle. After the regen was over. It stopped leaking.

The gauge inside the truck showed I went from 3/4 to 1/2 tank of DEF. So I drove about 20 miles to a truck stop, topped off the DEF tank, after fueling pulled forward out of the line and went inside truck stop to grab a bite to eat. When I came back to the truck. AGAIN, def puddle on the bottom. The DEF gauge showed it went from FULL Tank to 3/4 tank. I pulled out and parked in a parking spot. All the way to the spot it was leaking fluid. I then hopped on the highway and drove about 20 miles back to my yard. When I got to the yard, the DEF Fluid was no longer leaking. And DEF gauage read it still had 3/4 DEF.

The engine is derated. I connected INSITE, and it's showing the following codes:

3574- Aftertreatment 1 Diesel Exhaust Fluid Pressure Sensor-Data valid but below normal operating range.

1682- Aftertreatment 1 Diesel Exhaust Fluid Dosing Unit Input Lines-Condition Exists

It was too dark last night. And it was really late. I'm thinking it's some type of DEF Lines that carry the fluid, maybe? Anyone else had this issue in the past. I will upload a short video clip on youtube and post the link here in a few minutes.

BTW, this is a 2012 kenworth t660.
Click to expand...

I'm in the shop now with the same truck. Dealer said theres a recall on the def lines. All 4 of them are covered on the recall. Great news!

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