Review on Denso 234-9123 Oxygen Sensor: Reliable Air and Fuel Ratio Monitoring Device by Ickey Case

A perfect match for my 2006 Forester X. The parts are exactly the same as the OEM, right down to the terminal, connector and even the color of the insulator. Supplied complete with anti-seize lubricant. On some cars you can use a 7/8" or 22mm open-end wrench, but the '06 Forester just didn't have enough room to apply the torque required to loosen it. Bought a "goosefoot" type socket for use with one long extension cord and a breaker.Once it got away from the first part it was fairly easy to remove and replace under the hood.You just need to be a little acrobat..Disconnect the negative battery terminal while you work on it to erase the engine computer so it "learns" this new sensor. The car seems very difficult to start the first time after replacement. It's OK. Drive the car at full speed, turn off the batteries and without touching the accelerator or even the brake pedal (deprives the engine of vacuum and affects its operation) and let it idle for about 10 minutes until the temperature gauge indicating normal operating temperature and moving at idle speed. stabilized at normal speed. Then turn on the air conditioner to full power. , rear window, headlights, etc. and leave it for a few more minutes so that the computer learns to work with the sensor under load. My car has intermittently flashed check engine light codes related to catalytic converter performance below a threshold and even after trimming the catalytic converter. Rich. I'm swapping the inlet and outlet sensors to see if that fixes the problem. The originals have about 180,000 miles on the odometer and are probably defective or faulty. Both had some fluffy looking black soot, indicating heavy work.