# Need Help



## MadBlur (May 6, 2020)

So back to the same old goat with the T2.0: Low quality def.

So i've read almost everything here I can. I started carpet bombing it in hopes of fixing the issue. What I've found is this: The pump isn't pumping. 

First, I replaced the heater and reservoir mostly because I ordered the wrong part (thought it was pump) but it was cheap.
Removed both ends of the line from the injector and pump. Blew air through it to make sure it was unobstructed. about a 3" circle of fluid came out of the line onto the floor. 
Removed and inspected the injector for buildup or visible damage. Non observed. Reinstalled.
connected the lines and cycled the engine 30 times. maybe more. unhooked line from injector, no flow when cranking, idling, etc...
Reconnected the line, unhooked line from pump, Repeated process. Not one drop. 

Replaced pump. 100% same results. No flow. Code is reductant flow below limit: too low. 

Any ideas, or techniques i missed in priming the pump or bleeding the line? I am sure i missed something or I have another problem not telling it to pump.


Thanks,
J


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## boraz (Aug 29, 2013)

do you KNOW its sposed to pump just with cycling?

have you tried driving any miles?

yeah the car does a precheck, but i dont know if it checks def flow during that time or not


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## boraz (Aug 29, 2013)

are you android? 









BiScan for GM - Apps on Google Play


Adds PIDs and other features for a selection of Vehicles using Torque Pro.




play.google.com





with this app you can run a manual regen, that surely would get the def flowing


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## MadBlur (May 6, 2020)

boraz said:


> do you KNOW its sposed to pump just with cycling?
> 
> have you tried driving any miles?
> 
> yeah the car does a precheck, but i dont know if it checks def flow during that time or not


I don't know anything except that, i can't really drive it because i let my sisin law borrow the car and she had it towed back to the house locked at 4 mph max.


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## boraz (Aug 29, 2013)

MadBlur said:


> I don't know anything except that, i can't really drive it because i let my sisin law borrow the car and she had it towed back to the house locked at 4 mph max.


pretty sure it needs to be reset/regened before itll come cout of the shutdown


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## Detrious (Jul 5, 2017)

It takes some time before DEF starts pumping under normal circumstances. The system has to heat up first, injecting DEF into a cold SCR catalyst will do nothing, usually after a few miles of driving it has sufficient heat. Since the car is already stuck in limp mode it might not be able to generate enough heat to trigger this. If you can get that app running you can trigger a stationary regen that might do the trick. Once it gets hot and if the repairs worked it should clear your code.


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## MadBlur (May 6, 2020)

Detrious said:


> It takes some time before DEF starts pumping under normal circumstances. The system has to heat up first, injecting DEF into a cold SCR catalyst will do nothing, usually after a few miles of driving it has sufficient heat. Since the car is already stuck in limp mode it might not be able to generate enough heat to trigger this. If you can get that app running you can trigger a stationary regen that might do the trick. Once it gets hot and if the repairs worked it should clear your code.


thanks everyone. waiting for the Bluetooth dongle to get in. Expect to try it tonight.


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## MadBlur (May 6, 2020)

Did a def test. Pump is definatlely pumping... got sprayed in the face when i pulled the line off. So def test ran 15 mins and then quit. Def Light still there.

I have torque pro, bi scan, and gretio. 

Think i may need to do repair verification to get it to go away, but i dont know if it can be done away from the dealership.


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## MadBlur (May 6, 2020)

Any one know if any of these readings look off?


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## Detrious (Jul 5, 2017)

If that service bay test didn't clear it then somethings still up. There is an obvious NOx drop across the SCR so it is trying to work. Readings don't look terrible but I don't know GMs exact spec on NOx drop.

Have you been able to confirm the DEF concentration or at least confirm the fluid in the tank is fresh? I had a driver once buy a new bottle of DEF that was just straight water, threw a light because of the now reduced concentration, someone filled their truck with the DEF and returned it to the store refilled from a hose. If you can get access to a DEF refractometer I recommend checking to be absolutely sure.

If you are sure it isn't the fluid then the only other thing I can think of is removing the injector itself and looking for contamination. I've pulled some that have looked like this or worse from the dried buildup. It can inject some fluid in that state but not enough. Check inside the hole too because it is possible to dry in the pipe and cause problems. If you see any buildup you can clean it with warm water.

If not that then maybe NOx sensor 2 is reading higher than it should causing it to think the DEF is bad.


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