May 3 2015

How to replace downstream O2 sensor in 2005 Hyundai Tucson

If your check engine light is on in your 2005 Hyundai Tucson, you may have an issue with one of your O2 sensors.  This is an easy thing to replace yourself if you’ve done any work on a car, and you can save a ton of money doing it yourself.  (A local dealership wants $250 to replace it; I did it for less than $60.)

The first thing you should do is have the code read and figure out which sensor is the one that needs replacement.  You can go to an auto parts store to have them read the code.  In my case, I had two codes:

  1. P0136 – O2 Sensor Circuit Bank 1 Sensor 2
  2. P0140 – O2 Sensor Circuit No Activity Detected Bank 1 Sensor 2

Here is a great post which will help you figure out the correct sensor location.

Bank 1 is the bank of cylinders on the firewall side.

Bank 2 is the bank of cylinders on the radiator side.

Sensor 1 is the O2 sensor before the cat.

Sensor 2 is the O2 sensor after the cat.

If you have a 4 cylinder engine like I do, it is simple.  There is no bank 2, only bank 1.  Sensor 1 is the upstream sensor under the exhaust manifold heat shield (you can see it just by popping your hood) and sensor 2 is the downstream sensor.  Here is how you replace the downstream (bank 1, sensor 2) on a 4 cylinder 2005 Hyundai Tucson.

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