2000 PreRunner 2.7L... Air-Fuel Ratio Sensor location...

Ok, possibly rudimentary question but here goes. Where is the AFS (air-fuel ratio sensor) located? Is it simply a component that looks just like an oxygen sensor and it's just downstream from the exhaust manifold?

I need some help diagnosing a P0171 code and it appears that my AFS is stuck at .66v no matter what. The Launch CRecorder I'm using to capture data calls two different things oxygen sensors and I'm thinking that one is actually the AFS and the other is the OXS. Anyone here in the know and can shed some light on this for me?

 

That is the o2 sensor.

Front o2s (before cat) measure the air fuel mix leaving the cylinder. The o2s behind the cat just measure the air leaving the cat to make sure its working right. On newer stuff they play a bigger role but on 1st gen tacos they only monitor the cat.


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