P1091 — BMW — Pre-Catalyst Fuel Trim Too Rich Bank 1

P1091 (BMW): Pre-Catalyst Fuel Trim Too Rich Bank 1 — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Pre-Catalyst Fuel Trim Too Rich Bank 1. Source catalogue definition; confirm applicability using vehicle service information.

Affected system: Powertrain