The sensors are installed at the front and rear of the
Catalytic Converters. Prior to sensor removal, use a BMW scan tool to read out and clear ECM fault codes. To avoid damaging oxygen sensors, remove them before exhaust system or manifold removal, and do not mix up oxygen sensor connectors; mark connectors before disassembling. For a 6-cylinder engine, remove the intake manifold cover and separate post-catalyst oxygen sensor connectors. Working at the right side of the engine above the
Exhaust Manifolds, remove the oxygen sensor harness connectors from brackets, then separate connectors. Use a slotted 22 mm socket to remove the oxygen sensor. To access post-catalyst oxygen sensors, raise the vehicle and support it safely, then remove the front end reinforcement, ensuring not to drive the vehicle without it installed to prevent damage to the chassis or front end. For post-catalyst oxygen sensors, use a crow-foot wrench for removal. For a V8 engine, raise and support the car for access to the exhaust system and remove the oxygen sensor with a crow-foot wrench. When installing, coat sensor threads with anti-seize paste, noting that new sensor threads come pre-coated. Avoid overusing anti-seize paste and ensure the sensor tip remains uncontaminated. Finally, make sure sensor electrical harnesses are routed as before and connected correctly.