I just picked up a 2004 MDX Touring with 96k on the ODO, I plan on doing a thread with pics and a DIY on Tranny fluid change and some other items. The car is in great shape, one owner, no accident and garge kept.

Within the last week the check engine light came, thinking it was faulty gas cap I disconnected the battery and got the light to turn off. However three days later it came back on. I went to auto zoone to have them check the code before I went to the stealership to see if it was something simple. What came back was the following:

Catalytic Converter System, Below Efficiency P0420 - Bank #1

I went back into auto zone with the guy helping me and he did a search on his computer and told me that it was an O2 sensor. However I know that the car has 4 sensors with two of them being in bank one.

Does anyone know how to find out which one it would be, before I replace all of them and spend uneccessary money? Is this a hard fix, any DIY floating around, if not i will have to try and make one up.

Do I maybe just have a bad tank of gas? I am pretty sure that they should be repleced at 100,000 which for me is only a few thousand miles away.

Thanks for any help you guys might have!

 

p0420 is the rear catalytic converter. from what I know its not the weld in type. stealership prices can be steep as well as labor. clear code and see if it comes back again. Other wise with come hand tools and jack stands it can be done. Now your threads speaks of two things. an o2 sensor code or af sensor code are something like p0135. catalytic converter codes which is common on this model is p0420. Honestly clear it and monitor it.

 

i have the same message sensor 1 bank 1. I replaced the one next to the manifold by the spark plugs but the engine light has come back...this is a 2004 mdx..i can't find the other sensor.. Where is located?