Review on 🔌 Denso 234-9021 Upstream Heated Oxygen Sensor: Advanced 4-Wire Plug with 14.17” Harness by David Garnic

2003 Avalon XLS Bank 1 Sensor 1 replacement. The key to replacing a sensor is making sure you are working with the correct sensor. On the Avalon, Bank 1 Sensor 1 is located between the engine and the vehicle firewall. see photo gallery. I ran the engine for about 1 minute to warm up the manifold (but not hot), then sprayed some PB Blaster, waited a few minutes and then snuck in with a sensor extraction tool (https://smile.amazon.com/gp /product/B00390BS7C/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1). I used a standard socket wrench with a 10" metal tube to snap the O2 sensor in place. Once the sensor was loosened, it could easily be unscrewed by hand. Removing the connector was not easy. Bank 2, sensor 1 exposed on the front of the engine. Make sure you understand how to disconnect the wire before attempting to use Bank 1, Sensor 1 as you won't be able to see it. The main operation is to release the tab on the side of the connector, after which the cable can be freely removed. Replacing the O2 sensor wasn't difficult. Use anti-seize paste, hand-tighten, and then connect the cable. Note. You can't see the cable connector, but it only fits one way and locks into place. Then complete the tightening process with the extraction tool. When I started the car, the check engine light was still on. Disconnecting the battery resets all sensors and you're done. The total time did not exceed 30 minutes. Total cost $120 with probe, instrument and PB spray.