2002 - replacing o2 sensors

I have replaced all the 02 sensors (4) more than once. One I have replaced 4 times. The check engine light comes on and is always for this item. Why is this happening and how can I fix it? It is $150 -$200 every time.

Well, to the best of my knowledge your car only has 2 oxygen sensors, there should be one in the rear exhaust manifold and one just behind the catalytic converter.

I would also recommend not using either the cheapo sensors or the Bosch sensors.

Which sensor is it that is setting off the code? My guess is that it is the one behind the converter, meaning something is probably wrong with the converter itself instead of the sensor.

What code are you getting? can you give us some more info?

It could be 2 sensors. Both the dealer and an independent mechanic have stated that it has 4 (2 intake and 2 exhaust). I have had better luck with the after market sensors than with GM parts on this. The one changed the most is on the manifold. I will have to get it worked on again, since the light is on now. I will post the code #.

It could be 2 sensors. Both the dealer and an independent mechanic have stated that it has 4 (2 intake and 2 exhaust). I have had better luck with the after market sensors than with GM parts on this. The one changed the most is on the manifold. I will have to get it worked on again, since the light is on now. I will post the code #.


Well I know there are no oxygen sensors in the intake stream...thats hilarious to me.

There are a couple different sensors in the intake stream that can throw a code though, but they are not oxygen sensors. Get the code pulled out and get back to us though.

I went by Autozone and had the codes pulled up.

The first one is P0137 and states " The PCM has determined that the input voltage from oxygen sensor 2 in bank 1 is too low for current operating conditions. (oxygen sensor 1 is closest to the cylinder head before the catalytic converter, while oxygen sensors 2 & 3 are located further
downstream and are typically mounted in or after the catalytic convertor) (bank 1 identifies the location of cylinder #1, while bank 2 identifies the cylinders on the opposite bank)"

The second code is P0410 and states "The PCM has determined that a malfunction exists in the secondary air injection system."

From this I am inclined to think that the Catalytic Converter could be bad, as earlier stated. Does low voltage in the first code mean the same thing as the second code?

Thanks. I have recieved better comments from this board than all the mechanics combined.

Mark