I have a 2002 Toyota Corolla (engine 1zz-de) and I am trying to get to the bottom of a p0171 code. I've read from other posts that a faulty O2 sensor could cause the lean condition, so I have been testing those sensors with my scan tool. I was hoping someone could take a look at the screenshot attached and tell me if it looks like a faulty O2 sensor
- Test is made at idle after engine warmed up
- I am simply recording the O2 sensor (bank 1 Sensor 2) voltage
- I am seeing it remaining pretty flat for the first 20 seconds or so, then oscillating a little bit but not evenly between min (0.1) and max (0.9)
- Based on what I've read, this shows the sensor is faulty
- Question #1: do you agree that this sensor is faulty?
Note: my other O2 sensor (bank 1 Sensor 1) is oscillating much more nicely, with a 2.5 sec period. - Question #2: should the sensor not be oscillating much faster, with a 1 or even 0.5 sec period?