SES Code

[One_Bad_TA]

For awhile now my SES turns on/off periodically. I keep throwing the code P0157 02 sensor circuit low voltage B2S2. Hooked it up to a wave graph and the voltage is at about 0.065 V and does not fluctuate while the other 02 sensors do. My question is: Is my 02 sensor bad or going bad andif so how much can i look to replace it for? Thanks

[stanger88]

Check the base of the catalytic converter. A lot of them rust/crack right there b/c the AC condensation runs down it. This will cause what you are seeing. If I am thinking right, B2S2 is right hand side (pass) and rear sensor, which sounds right for my possible diagnosis.

If so, have a muffler shop weld it up and let the code clear, it will do so in a few hundred miles or so and then you will KNOW that you fixed it vs. just turning it off.

TO check for this leak, when the car is cold, take a squirt-bottle or glass of water and throw it where I indicated (base of the cat where the pipe is welded on) and you should see bubbles. Do this after a cold start, obviously.

[One_Bad_TA]

There is a crack but not at the bottom of the converter its at the top of it by the exhaust manifold. But not sure if that was the reason why the light would go on/off a few times a week. Im gunna take of the cat and get it welded and see if its just like the crack at the bottom of the converter.

[stanger88]

There is a crack but not at the bottom of the converter its at the top of it by the exhaust manifold. But not sure if that was the reason why the light would go on/off a few times a week. Im gunna take of the cat and get it welded and see if its just like the crack at the bottom of the converter.

EIther way, it would create an oxygen-rich atmosphere near the O2 sensor and this would lead to a "system low voltage". I assume you mean this crack is below the first O2, and above the 2nd? Sounds right. I think you have found your problem.