Oxygen Sensors & Catalysator

[giip]

Hi all,

I recently bought a JK and on the first day got the engine warning light on. I took it back to the dealer and they said that sensor readings are fine and something about using the cheaper fuel and I should use premium. I don't know much about engines, but I googled that sensors are to detect if the catalyst converters are working, which has not much to do with fuel type IMHO.

So, I bought ODB2 reader to see what is going on with sensors. I included captures from sensors 1 and 2 readings from bank 1, which were taken while driving 90km/h on motorway.

Would anyone be able to see if those are indicating bad catalyst converter or sensor(s)? To me it looks like sensor 2 might be not be steady enough i.e. converter is not working well enough, but I have lack experience on these.

[Banshee]

You can swap the sensors around, if you like, the left & right are the same. (Front with front, rear with rear.)

I would swap the 2 rear sensors over & run it again. If the problem swaps sides, it's a bad sensor. If it doesn't, then it isn't, and then it might be a bad cat.

I did that when I was getting the errors, and it turned out to be a bad cat in the '08.

[giip]

Hi Banshee,

Thanks for the idea. Only problem is that both sides are pretty much identical. I drove the same bit of motorway again plotting the bank 2 this time and the graphs of the bank 1 and 2 are very similar.

Cheers.

[Banshee]

If they are that close and only 1 side set a code, I'd be inclined to reset it & ignore it until it comes back, then look again.