Oxygen sensor help?

Question

I need the part # for a P0155 error on my 2003 Mitsubishi Montero Limited. Is it before the catalytic or after?

Answer 1

P0155 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
before the cat ther are 3 total on your car even though it says only1 replace the 2 befor the cat there supose to be replaced at 100,000 miles anyway and you will get better milage

Answer 2

an autopart store can help you. on most cars after 1996 you will have at least 2 on your car for 4 cylinders and 4 on v6s and so on. if a system is lean it means there is not enough fuel getting into the motor. if it is rich is means there is too much fuel. if it mentions a bank 1 or 2 this means its telling you which side of the engine it is one. bank one is the side of the engine that houses cylinder 1. an autozone can tell you which bank is which. sensor 1 means its before the cat and sensor 2 is after the cat. if you get a heater circuit malfunction it means the o2 sensor is not getting heated enough to do its job. the easiest way to get what you need is to hit an autozone. they will get you what you need. most 02 sensors run about 80 dollars. i have sold some as cheap as 30 and as expensive as 150

Answer 3

You may have 2 one before and one after.
If you only have one it will be before and if you are replacing one you should replace both if so equipped.
Your local parts house can tell you the part you need
Thanks Bill B
Also many parts stores will pull your codes for free in order to sell you the parts. Just call ahead and ask if they have the scanner available.

Answer 4

the oxygen sensors are found before the cat on the down pipe side you also have a oxygen sensor on the inlet manifold side of your engine

Answer 5

I think it may be in the converter. Have you called the dealer parts department. They have diagrams of where things are located.