My car is throwing an SES light and its the o2 sensor. I was told there are four o2 sensors on the car. Now, my question is, how do I find out which o2 sensor is bad, if possible? Thanks in advance.

Also, is it bad to use those "universal" o2 sensors?

 

Go with OEM O2 sensors.

 

An OBDII reader will tell you which one(s) are bad.

I use the universal ones.

 

Go to AutoZone... they will pull the code for you... probably a P0138/P0139.

 

What damages could it cause if you dont replace/fix them??

 

Sensor 1, Bank 1 and 2 control the a/f ratio in closed loop, which is when the car is warmed up and out of the open loop fixed control scenario. This means that the computer will try and maintain a 14.7:1 ratio. This is what you want to maintain and you want these to function.

Sensor 2, Bank 1 and 2 control ZIP. All they do is confirm that your primary cats are functioning properly. If they aren't then a CEL occurs but you still have the main cat which will still pass emission standards.

You will not cause any damage to your car with malfunctioning o2 sensors, just environmental damage.

 

up

 

Great response! I had the CEL but I just took it to the dealership and told them to reset it. The guy said it was caused by malfunctioning o2 sensor.

Should I just leave it or is it worth getting fixed?

 

The CEL will come back eventually. U will need to get it fixed to pass emissions.

 

Any ill effects? I have friends that use universal o2 sensors and have not had any problems but on Hondas.
I went to a local shop to check, and was told it was the o2 sensor. He didn't tell me which one, just that there are four of them. Will autozone be able to tell me the exact one thats out? Is there anything I can do at home to figure out which one it is?
I tried resetting it but it comes on when I give it a lot of gas (IE:trying to pass someone on the freeway).

 

AutoZone will give you the code... the code will tell you which one is giving you the SES light.