How to Replace the Lambda Sensor on the Toyota Yaris II

Lift the car and secure it. The sensor is located on the exhaust manifold. To facilitate removal, slightly warm the engine (not to operating temperature). Disconnect the electrical connector. If the sensor is stuck, spray some penetrating fluid (WD-40) on the thread. Use a specific 22 mm lambda sensor socket (with the appropriate cut for the wire) to unscrew the old sensor. If you are installing a universal sensor (which requires reusing the original connector), cut the connector from the old sensor. Be very careful with the wire colour coding. On Toyotas, the standard colours for a 4-wire sensor are Blue (signal), White (ground), Black (heater), and Black (heater). Refer to the wiring diagram of the new sensor (which we found on Amazon with code B0FCDVHD9F for £26.00) to correctly match the wires. Insert heat shrink tubing onto the wires before proceeding. Join the wires of the new sensor to those of the original connector using solder sleeves, then heat the heat shrink tubing to insulate the joints. Apply a high-temperature ceramic lubricant to the thread of the new sensor (do not use regular grease, as it may damage the sensor). Screw in the new sensor by hand to avoid damaging the thread; then tighten with a torque wrench. The correct torque is 40-44 Nm. At this point, reconnect the electrical connector, secure the wiring with the appropriate clips, and clear any error codes from the ECU.