Engine Drivetrain 2nd Gen S Most liked posts in thread: Need some help troubleshooting an O2 sensor.

Hi,

You are correct the bank one sensor two voltage does fluctuate from 0 volts when you let off the gas up to about .895 volts if lead footing it. At a steady 2000 to 2500 rpm at highway speeds holding a constant speed you should see a figure very close to .7 volts. It will fluctuate a little as about every 5 minutes or so the ECU will temporarily richen the mixture to test the response of the O2 sensor. At these times you will read .855 volts or so with it quickly dropping back down in just a few seconds.

 

Forgot to add a couple of other thoughts. The steady state driving I mentioned above, that is when the O2 sensor is operating in closed loop and the ECU monitors levels. When your driving it like ya stole it the system goes into open loop mood as its impossible for the ECU to monitor cat efficiency with load varying up and down. If my memory serves right the P0136 is because the spacer removes flow from the O2 sensor and it doesn't respond quickly enough to the tests I mentioned. The P0141 is because with the O2 sensor is spaced out so it gets below 600 degrees and the heater circuit has to come on again. This can eventually burn out the heater element.

 

Don't mean to hijack this thread, but does Ultra Gauge or Scan Gauge show O2 sensor voltages?

 

Not sure if they do or not. I use DashCommand with an iPhone and wifi OBD adapter. It will specifically measure post cat O2 sensor. The PID to monitor is Voltage Bank 1 Sensor 2 under O2 PIDs when Data Logging.