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Hi, new forum member & new Colorado diesel owner. I took ownership of a Z-71 4 door short box in November (2019 model year). It has been a great truck with the exception of some emission related issues. I will explain the situation and see if anyone else has experienced the same issues and can offer some advice because my dealer does not give me a warm fuzzy feeling on solving the issue (numerous emails & calls and two shops visits so far)....
In mid February, at about 3,500 miles on the odometer, I had a CEL and the following two codes as verified with my code reader and dealer: P244A (DPF differential pressure too low bank 1, and P226D DPF deteriorated/missing substrate bank 1. The first trip to the local dealer cleared the faults and they said if the faults show up again, we will order & install a new DPF. Well the faults came back in a short time and they did indeed install a new DPF. The new filter worked fault free for about a week and the same two faults have re-occurred. On top of the faults, I also got the “engine power is reduced” message and it was indeed reduced. These faults have been clearing on their own or I have been clearing them with my code reader. I will also throw in I live in northern Minnesota and saw plenty of action in the -20 to -30 below zero temps during this time. The truck has been starting great both plugged in and not, so no issues there. Also curious is the DEF usage is all over the map according to my DEF % gauge. It may go way longer than the GM estimated usage amount or go way shorter before the gauge changes. Before the dealer changed out the DPF, it stayed at ~90% for a month or so (it was very cold during that time). So for anyone with experiences with these faults, maybe they can chime in and advise on the situation. I get the feeling this will be a lengthy troubleshooting exercise for the dealer, and I would rather drive my truck than some loaner vehicle. Here are a few questions I have and have not been able to find concrete data on:
Is the lack of DEF usage (according to my % use gauge) anything to be concerned about? It freezes at 12°f and is maybe a block of ice all winter (where I live). The DEF level does vary +/- a few % at times, not sure how it can measure frozen material or how good the heaters work for melting the DEF ( I guess it is slowly trending downward over time indicating some usage).
Concerning the two faults, I have seen no indication if regens are occurring as I drive. Hard to believe one DPF was plugged (as the dealer thought), and then have the same faults occur with the new DPF (looking as if this one is plugged also).
I don’t quite understand if there is an interaction with the DEF and the DPF, as diesel fuel is injected into the SCR converter to create the high temps needed for the DPF rejen cycle and NOX reduction. So life goes on without DEF use? Isn’t that what other manufactures got in a jackpot over?
It is shitty weather to be crawling underneath the vehicle, but I do plan to check on the emission related components (wires, leaks, and connections, etc) while working with the dealer in hopes this does not turn in to a lemon law situation because I really like what the truck offers. The delete routine might solve all of this, but I hate to void the warranty and piss off mother nature. Thanks for any advice on the matter…
In mid February, at about 3,500 miles on the odometer, I had a CEL and the following two codes as verified with my code reader and dealer: P244A (DPF differential pressure too low bank 1, and P226D DPF deteriorated/missing substrate bank 1. The first trip to the local dealer cleared the faults and they said if the faults show up again, we will order & install a new DPF. Well the faults came back in a short time and they did indeed install a new DPF. The new filter worked fault free for about a week and the same two faults have re-occurred. On top of the faults, I also got the “engine power is reduced” message and it was indeed reduced. These faults have been clearing on their own or I have been clearing them with my code reader. I will also throw in I live in northern Minnesota and saw plenty of action in the -20 to -30 below zero temps during this time. The truck has been starting great both plugged in and not, so no issues there. Also curious is the DEF usage is all over the map according to my DEF % gauge. It may go way longer than the GM estimated usage amount or go way shorter before the gauge changes. Before the dealer changed out the DPF, it stayed at ~90% for a month or so (it was very cold during that time). So for anyone with experiences with these faults, maybe they can chime in and advise on the situation. I get the feeling this will be a lengthy troubleshooting exercise for the dealer, and I would rather drive my truck than some loaner vehicle. Here are a few questions I have and have not been able to find concrete data on:
Is the lack of DEF usage (according to my % use gauge) anything to be concerned about? It freezes at 12°f and is maybe a block of ice all winter (where I live). The DEF level does vary +/- a few % at times, not sure how it can measure frozen material or how good the heaters work for melting the DEF ( I guess it is slowly trending downward over time indicating some usage).
Concerning the two faults, I have seen no indication if regens are occurring as I drive. Hard to believe one DPF was plugged (as the dealer thought), and then have the same faults occur with the new DPF (looking as if this one is plugged also).
I don’t quite understand if there is an interaction with the DEF and the DPF, as diesel fuel is injected into the SCR converter to create the high temps needed for the DPF rejen cycle and NOX reduction. So life goes on without DEF use? Isn’t that what other manufactures got in a jackpot over?
It is shitty weather to be crawling underneath the vehicle, but I do plan to check on the emission related components (wires, leaks, and connections, etc) while working with the dealer in hopes this does not turn in to a lemon law situation because I really like what the truck offers. The delete routine might solve all of this, but I hate to void the warranty and piss off mother nature. Thanks for any advice on the matter…