O2 Sensors replacement

[JFP in PA]

Originally Posted by hancock1701

I'm in the same situation, and mine is due this month. I've read that O2 sensors that don't work properly will give you codes. Moreover, they say that if those stay within the correct voltage range (0.1 to 0.9 in this case, and downstream should try to stay at ~0.7 consistently, then they are OK. But I've also read that there are cases when O2 sensors get tired, and haven't triggered a code yet, but will affect their response time.

Anyway, you can get the Bosch ones from Amazon or RockAuto for about $80 to $100. The Universal one, which requires you to do the connector, is even cheaper at $60.

Here are the voltages for my working bank 1 and dying bank 2 cats.

You have a bad cat, not bad O2 sensors:

[thom4782]

JFP and others are right. If your sensor voltages are in spec and your read O2 readings are sine waves instead of essentially flat, your cats are cooked.

CA no longer does a tailpipe test for '00 and later cars. To pass, your CEL must be off, your monitoring systems should be ready, and I believe you mustn't have and stored emission codes.

If you have a Durametric, check the O2 sensor voltages to confirm the problem. A few days before testing, clear CEL and stored codes. Drive the car several times until the monitoring systems reset. Then get the car tested.