Source-backed diagnostic reference

P1091 EV diagnostic code

Pre-Catalyst Fuel Trim Too Rich Bank 1

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

BMW: Pre-Catalyst Fuel Trim Too Rich Bank 1 Source
SUBARU: Tumble Generator Valve #1 RH Malfunction Stuck Close Source

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