Hello all,

My XJ is having O2 Sensor troubles. It's throwing codes P0135 and P0138. I know that it's O2 sensor trouble, but I have been unable to figure out exactly which sensor I need to replace or if its both. I think that it's both of them, but I'd rather not spend the money on both if I'm just misreading the codes. I believe that the downstream sensor is throwing the P0135 and the upstream sensor is throwing the P0138. Am I correct in that? I've also read that the P0135 could be caused by a blown fuse, but also that that fuse going out would result P0137 code as it would take out power to the sensor. Is that correct? Just wanted to check my reasoning before I start spending money.

Additionally I know that the NTK sensors are considered the best replacement options, however, I can not seem to find them anywhere. Does anyone know where I can find them?

Thanks for the assistance.

 

The NTK upstream and downstream sensors are on unknown backorder. NTK23179 which is for both up and downstream is available at lots of parts stores. You can go to NGK/NTK web site and see what sensors are available for your ride.

 

Thank you. Are there any known issues using the NTK23179 on both positions?