Req'd fix for Gen 3

3.4 Additional Requirements for Generation 3 2.0 Liter Subject Vehicles: In
addition to the requirements of Paragraph 3.1, each Proposed Emissions Modification for a Generation 3 2.0 Liter Subject Vehicle must also:

3.4.1 Require the future installation of OBD hardware and software to achieve
compliant SCR monitoring, including the addition of a Second NOx Sensor in a
Subsequent Service Action according to the mileage intervals and schedule described in subparagraph 3.4.3 (i.e., full volume SCR system monitoring with a downstream NOx sensor).

3.4.2 Describe the NOx sensor or DEF system capable of detecting poor
reductant quality, including emission and dilution detection levels, and how the vehicles will detect poor quality DEF and initiate Inducements, and require the installation of such strategies.

3.4.3 Require the installation of the Second NOx Sensor and a new DOC or
DOCs (if necessary to ensure compliant emissions performance for 150,000 miles) according to the following mileage intervals and schedule:
i. If, in the Proposed Emissions Modification, Settling Defendants
demonstrate durability of the current DOC for 90,000 miles, then Settling
Defendants must install the Second NOx Sensor and the new DOC at
90,000 miles or by January 1, 2020, whichever comes first, in a single
Subsequent Service Action.

ii. If, in the Proposed Emissions Modification, Settling Defendants
demonstrate durability of the current DOC for 120,000 miles, then Settling
Defendants must install the Second NOx Sensor and the new DOC at
120,000 miles or by January 1, 2020 whichever comes first, in a single
Subsequent Service Action.

iii. If, in the Proposed Emissions Modification, Settling Defendants
demonstrate durability of the current DOC for 150,000 miles, then Settling
Defendants are not required to replace the DOC and must install the
Second NOx Sensor in a single Subsequent Service Action beginning in
the 4th quarter of 2017, to be completed by January 1, 2020.

3.4.4 Comply with the OBD requirements under Cal. Code Regs. tit. 13 ... snip...

Compliant levels ≤ 0.240 g/mile NMOG + NOx and ≤ 0.0175 g/mile PM

Look @ http://pics3.tdiclub.com/data/517/820433_EA288.pdf
page 46, for a good idea of stock sensors in EA288.

I dont see any NOx sensors in there, so not quite clear why they talk about "Second NOx Sensor".

The fix also provides explanation for 2nd service visit: it is for the installation of the NOx sensor, in 3.4.3(i/ii/iii)

3.4.2 Describe the NOx sensor or DEF system capable of detecting poor reductant quality, including emission and dilution detection levels, and how the vehicles will detect poor quality DEF and initiate Inducements, and require the installation of such strategies.
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I don't see how this is related to the scandal at hand. Would the fix described above have been something that would have been initially required for tdi's to get certified for the US market? Something does not add up?

I have a funny feeling - nothing more - that the apparent inadequacies in the diagnostics of the Gen 2/3 AdBlue systems and SCR catalysts became apparent during EPA/CARB's detailed analysis of how the system works in the fallout from the initial scandal.

"these systems are emitting higher-than-allowed NOx ... why isn't the OBDII detecting it? ... Oooooohhhh, there's no sensor for it!!! ... and what happens if the DEF/AdBlue isn't up to spec and that's the cause of the higher-than-allowed NOx that isn't being detected? ... Ooooooohhhh, the sensor they have doesn't work in the real world!!!"