ATC Codes for deterioration

UncleDave

Seasoned Expediter
Owner/Operator
Offline
Getting this consistently on my 19 258. DX3, shows inactive when scanning, but turtle light appears and wont regen. Clear codes, clear DPR reset, Run a Force Regen and it only lasts 1 min and says its done. Any ideas? Clears and then you can drive for 1-5 days and its back. Dealer has been 0 help. Anyone? Need a little help before I decide to sell and get rid of it and start over. 150K, always serviced, never had a issue till now. Software from DX3 is current, no updates avail to Firmware.
 

greasytshirt

Moderator
Staff member
Mechanic
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The cure for P0421 is to replace the ATC. Expect the upper temp sensor to fight you on the way out. This is a fairly common problem, IDK why your dealer is confused.
 

UncleDave

Seasoned Expediter
Owner/Operator
Offline
Thanks for your honest upfront answer and help. My situation is I have 2- 2019 258's 195K and 155K. Both are showing the same codes. What I meant by dealer being confused is that they cant determine how to help. They want almost 1000 per truck to diag, which is insane, because all they want to do is charge charge charge, and not give any help or advise.

Any way rant over.. So... I replace ATC, and the upper temp sensor as a precaution, reset codes and we should be good to go? Is the usual mileage for replacement just under 200K? Anything else I need to know that's coming down the pike at me? Already had DPF cleaned 30K ago..

Once again. you are a treasure trove of great info.. thanks for all you do.

Dave
 

greasytshirt

Moderator
Staff member
Mechanic
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I haven't personally learned the patterns of ATC failure yet. So far it seems sort of random. There's a TSB on this, too (your dealership should know this. The TSB says "Got a P0421? Replace ATC".)The TSB lists all the hardware and gaskets and stuff they recommend replacing, but it's not complete. You will want to get the four studs at the bottom flange because they're impossible to remove from the old one. Maybe the three studs that hold the aftertreatment injector on, too. And the two copper washers that go on the aftertreatment injector banjo bolt. Everything else can be reused.

Afterwards, I'd jump on DX, check the exhaust brake setting, go to the engine customization menu, set the PM amount to 2.5, and do a regen while looking at exhaust temps.

I hear the most absurd dealership stories from you guys. Unbelievable.
 
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