Mitsubishi Lancer Rear Oxygen Sensor 1588A171/149100-6900, precise air-fuel ratio control

Mitsubishi Lancer Evolution wings 1.8L/2.0L (2010–2015) rear oxygen sensor (OEM 149100-6900, replaceable 1588A171) uses the same zirconia ceramic element and laser-welded process; air–fuel ratio signal accuracy ±1%; bench-tested lifespan over 100,000 km. It monitors exhaust oxygen content and provides feedback to the ECU to precisely control fuel injection, improving combustion efficiency and reducing emissions. Replacement difficulty moderate; use a dedicated oxygen sensor socket and perform cold-start installation to avoid thread galling.