Diesel Oxidation Catalyst 40K/70K?

peq

Member
Joined
Oct 8, 2015
Location
MD
TDI
2015 Golf Sportwagen TDI S 6M
I have a 2015 GSW TDI S Manual at 38K. I just scheduled my fix in mid-December (phase 1 & 2 at the same time, IIUC).

I'm confused about the following text:

"Phase 2 of the emissions modification will involve outfitting your car with new emission control parts to ensure system reliability and durability over time. We will install a second nitrogen oxides (NOx) sensor and corresponding software to improve the performance of the on-board diagnostic (OBD) system. In addition, the Phase 2 update will include installation of a new Diesel Particulate Filter, Diesel Oxidation Catalyst, and Selective Catalytic Reduction Converter. These components are needed to maintain emissions performance for the full useful life (150,000 miles) of your vehicle. If your vehicle has accumulated less than 40,000 miles (for automatic transmissions) or 70,000 miles (for manual transmissions) at the time of your Phase 2 update, your car may need to have the Diesel Oxidation Catalyst replaced a second time before it reaches 150,000 miles."

In particular, my questions are:

What is the difference between manual and automatic with regards to the Diesel Oxidation Catalyst? Why did they put a threshold at 40K and 70K respectively? It looks like during 110K miles (for auto) the Diesel Oxidation Catalyst is expected to have to be replaced since it's going to reach it's lifetime during that period. But for manual, this is 80K? In other words, if I have a manual and perform phase 2 fix at 69K, I'm expected to need to go through 2 Diesel Oxidation Catalysts during the remaining 81K. But what if I did my phase 2 much earlier (38K in my case)? Would I go through 3 catalysts?

Please un-confuse me :)
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
My guess is that with a manual the ECU is slightly different with fuel and other things during shifting compared to the DSG? Extra weight of the DSG? Added cooling needs of the DSG/cooling loop? I really don't know, just grasping at straws.

Also for verbiage, remember the lawers got to write the book with guidance of the engineers, I believe the DOC/DPF/SCR are all one unit, so it may be the dosing of the SCR is the real issue, and what will fail early, but they just call it a simpler name or something, again I could be mistaken.
 
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