I have a 2000 Mitsubishi Galant ES 2.4L Engine with California emissions. Installed is a new federal catalytic converter assembly. The problem is that I do not know what kind of oxygen sensor to install into the assembly, because the vehicle is from California. I am looking for a solution that requires me to NOT replace the entire assembly since the assembly is brand new.

Are there adapters available that convert the oxygen sensor's plug from federal to California?

2 Answers 2


Looking at the description of the California O2 sensor for your car, the only thing different on it (besides the internals) is the electrical plug. The wrench which you tighten it down with is 7/8", which means the sensor bung should be the same size as well. I don't think there is any real external difference between the California and non-California sensor. You should be golden here.

If the car came with California emissions on it (and it's no longer garaged in CA), you'll still want to put a CA O2 sensor on it or it will probably throw a code. The reason is, the vehicle computer will be looking for a certain input from the sensor. If it is getting readings something other than what it expects, you get an exception and a check engine light. The CA O2 sensor should fit right up into the new cat ... the bungs are pretty much standard on all American vehicles (and probably most other vehicles through out the world as well).


Just to add to the other answer as I ran into this same issue, what kind of emissions do I have on my mitsubishi galant? I had this code: P0421 and I had to replace my O2 Sensor & the catalytic converter but I wasn't sure if I needed the CARB (California Air Resource Board) compliant ones or not.

There is a label that identifies what type you have. I don't have the CA emissions car and here is the link to the RockAuto Parts page that showed it. It also showed where the label was located on the car.

enter image description here

The Non-California label: enter image description here

and the California label: enter image description here

  • Great find. You should finish it out by showing the image of where the stickers should be located. Dec 24, 2015 at 12:34
  • It took lots of searches on Google, but Yes I was happy when I found it and I would have, but I wasn't sure if it would all fit in the page. Dec 25, 2015 at 7:16

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