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Old 03-09-2019, 04:27 PM
chessy56 chessy56 is offline
Join Date: Jan 2006
Location: South Milwaukee, WI
Posts: 230
Default 2017 L5P with P20EE code

2017 Silverado, L5P w/81K miles. Starting to get code P20EE which suggests a "low catalyst efficiency". I can clear the code with my Edge and drive for a certain number of miles without the code reappearing- but, it eventually returns. I've seen some owners claim the #2 NOx sensor or the DEF injector may be the culprit.

Question: is there a problem driving this thing in the near term without major problems? I can force a "mobile regen" via my Edge, so I believe my DPF is being serviced. Maybe a flakey NOx sensor? A carboned/dirty DEF injector nozzle?

Where on the exhaust stream are these injectors and sensors physically mounted (any pics/diagrams) available? Any thoughts or suggestions?
So. Milwaukee, WI
'01 2500HD, LB7, 440K miles
"Stock" engine. Dual fuel filtration system with Kennedy lift pump, BF Goodrich Commercial T/A Traction tires (sold to a dude from Texas- it's living a warmer life just fine down there now!).

'17 2500HD, L5P (Happy Birthday/Merry Christmas to me!!!) Currently bone stock, 90K miles.

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