Source-backed diagnostic reference

P3400 EV diagnostic code

Faulty Cylinder Deactivation System

Reference status: This page preserves source-backed code definitions for discovery. Manufacturer/model applicability, repair steps and safety conclusions are not treated as verified unless a manufacturer-specific verified report is available.

Reference definitions

AUDI: Faulty Cylinder Deactivation System Source
GENERIC: P34C8 Source
GENERIC: Cylinder Deactivation System Bank 1 Source

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