I have a P2195 trouble code with my 2007 Toyota Sienna CE. This is O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1.

It's a little confusing but if I am reading my Haynes manual correctly, the repair goes as follows:

  • The sensor for 2007 and later models will be in the exhaust pipe after the catalytic converter.
  • To remove it, it's necessary to remove the passenger seat, disconnect and snake the pigtail through the grommet in the car floor. Then, disconnect the O2 sensor from underneath the van and replace.

Has anyone on this forum done this repair on a 2007 Sienna? If so does the above description sound accurate for how to fix it? Do you have any suggestions/advice for someone attempting the repair for the first time? Also, any advice for where to buy the replacement O2 sensor?


I think your looking at the procedure for a rear o2s b1s1 is an AFR sensor and is mounted on the firewall side manifold.

I'd also suggest you do or have some diagnostics done before you replace the sensor. AFR sensors are not cheap and you may find yourself throwing a few hundred dollars down the drain.

Check fuel trims. Check for vacuum and exhaust leaks. Check rear O2 sensor operation. Do a range test, pull a vacuum hose and watch AFR sensor voltage. Add an external fuel source and watch for changes in voltage.

  • Thanks Ben I've been doing more checking and you're right, it's actually an AFR sensor and it's tricky to change due to limited space. Jul 20 '16 at 16:51

It looks like based on this page http://www.ecatalytic.com/oxygen-sensor-education/oxygen-sensor-locations that I need an upstream right or rear sensor. The denso part number is 234-9012 and runs around $100. I've seen online that it's a p.i.t.a. to change out this sensor. I will do some checking into how to do a vacuum and exhaust leak check, etc. before replacing the air/fuel sensor.

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