3.0 Duramax P204D

[bmcbass]

Not sure if there is much info out there on this yet so I thought I'd share.

 

I have a 2020 Silverado z71 crew cab w/ the 3.0 Duramax turbo diesel engine. 

 

I'm in Manitoba Canada and when the temps got really cold (-40C overnight, -35C daytime highs) i started having trouble with the DEF system.   I had recently filled it and a couple thousand km's later in the cold it said it was near empty and i had a few hundred km's til it would be speed limited to 104km/h.  Filled the tank... it didn't take much fluid.  I park inside a garage overnight where when its -35 outside it might be -20 in the garage.   Next day i go to work, park outside in the -35 ish weather. Came out, started right up, about half a km from work i got the low def speed limited warning again, plus service emissions system message as well as check engine light.

 

Dealer diagnosed and found code P204D.  No service bulletins for this code.  They replaced the DEF tank and a few components.  Looks like it came as a unit.  They were to replace the reductant pump and sensor assembly, but looks like they just put in a whole tank.  

 

Part number for the tank looks to be 84914535.

 

I'm sharing this because there were 4 trucks (GMC and Chevy) on the lot with the same problem as mine, so its obviously a common problem, perhaps its induced by cold weather, who knows.

 

Overall I love the truck, the power is good, fuel economy is quite good, tows my 25' Rockwood camper with ease and fits the 5 of us just fine.  Hope this is just the bugs getting worked out as there is another problem I've seen posted here regarding a charge air coolant pump code P3196 that has shown up as well. 

 

Cheers 

 

 

[redwngr]

 

P204D is an issue with the reductant (DEF) pressure sensor circuit voltage out of range on high side. 

 

 

 

[Rubyralph]

 

On ‎3‎/‎1‎/‎2021 at 5:40 PM, bmcbass said:

Not sure if there is much info out there on this yet so I thought I'd share.

 

I have a 2020 Silverado z71 crew cab w/ the 3.0 Duramax turbo diesel engine. 

 

I'm in Manitoba Canada and when the temps got really cold (-40C overnight, -35C daytime highs) i started having trouble with the DEF system.   I had recently filled it and a couple thousand km's later in the cold it said it was near empty and i had a few hundred km's til it would be speed limited to 104km/h.  Filled the tank... it didn't take much fluid.  I park inside a garage overnight where when its -35 outside it might be -20 in the garage.   Next day i go to work, park outside in the -35 ish weather. Came out, started right up, about half a km from work i got the low def speed limited warning again, plus service emissions system message as well as check engine light.

 

Dealer diagnosed and found code P204D.  No service bulletins for this code.  They replaced the DEF tank and a few components.  Looks like it came as a unit.  They were to replace the reductant pump and sensor assembly, but looks like they just put in a whole tank.  

 

Part number for the tank looks to be 84914535.

 

I'm sharing this because there were 4 trucks (GMC and Chevy) on the lot with the same problem as mine, so its obviously a common problem, perhaps its induced by cold weather, who knows.

 

Overall I love the truck, the power is good, fuel economy is quite good, tows my 25' Rockwood camper with ease and fits the 5 of us just fine.  Hope this is just the bugs getting worked out as there is another problem I've seen posted here regarding a charge air coolant pump code P3196 that has shown up as well. 

 

Cheers 

 

 

I have had DEF related CEL(s) since new, I now have ~4K miles and have had at least 4 CEL at the dealership, they just replaced the following parts:

84914535 tank, 84620945 harness, 84714454 controller, and 3 1/2 gallons of DEF fluid. My issues began when new from the factory when the same dealer said that the DEF pump connector pins were wired wrong!

I hope this resolves my DEF problems as I plan on some long road trips this summer and I really want to enjoy the truck but I'm losing all hope of it being repaired correctly, which is a shame because I love the drivetrain of this truck.     

Edited March 5, 2021 by Rubyralph
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