Hi,

Is the mass a/f sensor or oxygen sensor is covered under drivetrain warranty?
I remember 2 years back toyota dealer told me that oxygen sensor is faulty and need to be replaces and infact they had replaces A/F sensor for about 400$. Is A/F sensor and oxygen sensor same thing or dealer just told me one thing and replaces the other part?

Thanks
--rubs

MAF and O2 sensors are different things, i think thet're covered under the engine warantee

Yes... They are a part of the engine, they are covered under warranty.
An A/F (Air/Fuel) sensor is a type of oxygen sensor. Oxygen sensors read the amount of oxygen contained in exhaust gasses. There are a half dozen basic types. Some generic replacements cost $25-35, some run up to $90.

You are confusing your o2 sensor with the air sensors that tell the computer how much air is entering the engine.
AFM Air-Flow Meter, (vane flap, vafm)
MAF Mass Air-Flow, (hot wire)
MAP Manifold Absolute Pressure, (pressure sensor)
KV Karman Vortex (creates vortice of air & passes light, or sound waves to measure frequency)

Are all types of air sensors.

That is correct but i am not sure why the dealer told me that oxygen sensor is bad and replace the Mass A/F sensor where infact i was reading that mass a/f sensor is only installed in the cars in CA and all other cars have oxygen sensor.

Yes... They are a part of the engine, they are covered under warranty.
An A/F (Air/Fuel) sensor is a type of oxygen sensor. Oxygen sensors read the amount of oxygen contained in exhaust gasses. There are a half dozen basic types. Some generic replacements cost $25-35, some run up to $90.

You are confusing your o2 sensor with the air sensors that tell the computer how much air is entering the engine.
AFM Air-Flow Meter, (vane flap, vafm)
MAF Mass Air-Flow, (hot wire)
MAP Manifold Absolute Pressure, (pressure sensor)
KV Karman Vortex (creates vortice of air & passes light, or sound waves to measure frequency)

Are all types of air sensors.

Are these sensors covered under federal emission policy or drivetrain?

That is correct but i am not sure why the dealer told me that oxygen sensor is bad and replace the Mass A/F sensor where infact i was reading that mass a/f sensor is only installed in the cars in CA and all other cars have oxygen sensor.