Service bulletin Circular 23Z9

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

NHTSA's summary

Audi is releasing a software calibration update to the Approved Emissions Modification (AEM). This software calibration will include the following changes to the vehicles emissions control and on-board diagnostics (OBD) software: (1) It will correct an issue that is causing the 'check engine' light to falsely illuminate under certain driving conditions, which has resulted in replacement of the diesel oxidation catalyst (DOC) for certain customers; (2) It will reduce the likelihood of experiencing an engine shudder that could occur during certain warm-up driving conditions; and (3) It will improve OBD monitoring of vehicle emissions systems and otherwise improve the software used by your vehicle.

The document

• NHTSA's copy of the document (PDF)
• If that address does not open, try this one

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system, Engine, Equipment and accessories, Exhaust and emissions, Software

Listing a model year does not mean every vehicle of it is concerned: the document says which.

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