Rep Power: 0

Hey guys so my check engine light came on the other day. I scanned the code found that it was a P0138

"O2 Sensor circuit high volts (Bank 1 Sensor 2)"

This code was on the computer twice. Anyways sounds like my O2 sensor is gone which makes sense my gas mileage has been done for the last 2 months. i usually get about 600km per tank but only getting 500km lately. Anyways is it safe to assume its the O2 sensor and get it replaced? Or could it be something else? Also is there any guides on changing O2 sensors on this website or anywhere else? This will be my first time.

 
Rep Power: 811

its pretty easy, but you do need the special tool and jack the car up. i just replaced both of mine recently, make sure you get the bosch oe type with the connector plug and also they are different parts for primary and secondary.

 
Rep Power: 237

there is a special o2 sensor tool? i just took mine out with a crescent wrench

 
Rep Power: 0

there is a special socket which has a slot where the wiring can go through but you could use a crescent wrench as well. You would need the tool to attach to a torque wrench though.

 
Rep Power: 0

hey guys so the light went off. But it has already come on and gone off once before? Does this mean it could be something else? Or is it still probably the sensor?

 
Rep Power: 237

Its still probably the sensor. Mine does that too. It will start to go out and then be ok for a while then throw a code again. Before too terribly long it will go out for good. Another thing though is if you are running rich for long periods of time it will make your sensor act up. As long as your AFR's are good, the sensor is just going bad.

 
Rep Power: 811

its prolly for a slow response code. it may barely go back to spec and turn off the light, but it always comes back. just means time to replace em. it will affect fuel mileage maybe 1-2mpg but nothing serious.

 
Rep Power: 0

Hey guys im replacing the sensor this week. Quick question though. Is this the sensor before or after the Cat? There is only 2 right? Also if its acting up because its running rich what should I be checking?

 
Rep Power: 811

for the EX, there is the secondary sensor inside the cat, for emissions only. the primary sensor is in the downpipe and thats the one important for a/f ratios. they are two different sensors and if you get the wrong one, the car wont work right. for the LX, since the cat is part of the exhaust manifold, they are just closer together but the top one in the header is still the primary.

 
Rep Power: 0

Mines the EX, is the code comming from first sensor or second sensor? Or the one in the cat?

 
Rep Power: 0

Can anyone tell me which sensor it is so I make sure I replace the right one?

 
Rep Power: 811

first sensor is in the downpipe, second sensor is in the cat for an EX. im assuming bank 1 sensor 2 is referring to the cat sensor. while youre at it, might as well replace both together. usually when one goes bad, so does the other.

 
Rep Power: 0

K thanks

 
Rep Power: 388

There is another code for a slow response, I got it two days ago.