Service bulletin NCU - 2023070021

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

Mercedes-Benz AG (MBAG), the manufacturer of Mercedes-Benz vehicles, has determined that the software for the engine control unit in the subject vehicles may not meet current specifications. Any catalytic converter aging might not be immediately detected and therefore, the check engine Malfunction Indicator Lamp (MIL) may not illuminate as required. After a cold start in the "catalytic converter heating" operating mode, misfires might occur, and the check engine MIL would be illuminated. Consequently, these issues may not meet regulatory requirements for on-board diagnostics and/or exhaust gas emissions MBUSA will conduct a voluntary Emissions Recall Campaign in which an authorized Mercedes-Benz dealer will update the software in the affected vehicles.

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, Exhaust and emissions, Catalytic converter

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

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