Source-backed diagnostic reference

P2251 EV diagnostic code

Exhaust leak, Oxygen sensor failure, Powertrain Control Module (PCM) failure, Wiring issue

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: Exhaust leak, Oxygen sensor failure, Powertrain Control Module (PCM) failure, Wiring issue Source
GENERIC: O2 Sensor Negative Current Control Circuit/Open Bank 1 Sensor 1 Source
GENERIC: O2 Sensor Negative Current Control Circuit (Bank 1 Sensor 1) Source

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