P1131 (Mazda): HO2S Bank 1 Sensor 1 Signal Below 0.45v AF Ratio Too Lean — what it means, the affected system and what to check before replacing parts.
HO2S Bank 1 Sensor 1 Signal Below 0.45v AF Ratio Too Lean. Source catalogue definition; confirm applicability using vehicle service information.
Affected system: Powertrain