It is located in the Y pipe of the exhaust.
There are four total oxygen sensors. One before and one after the catalytic converter on each side of the engine.
O2 sensors are always located on the exhaust system.O2 sensors are always located on the exhaust system.
The oxygen sensor on the 1999 Oldsmobile Cutlass Sierra is located on the lower exhaust. If you need to replace it, they are available for about $20 online.
The O2 sensors are screwed into the exhaust system. Follow the exhaust backward from the engine and you will find the sensors.
The upstream oxygen sensor is located in the exhaust pipe between the exhaust manifold and the catalytic converter The downstream oxygen sensor is located at the catalytic converter outlet
AnswerThere are three O2 Sensors on my 1999 Cougar. Two are located just before the Y-Pipe and are both wired to the drivers side of the Y-Pipe. The other is located just after the Catalyic Converter.Easy to change.
There should be one in the header and one more in the catalytic converter.
The TCM is the transmission control module and it has nothing to do with oxygen sensors!
The air flow sensors are located on the intake tract between the air filter and the throttle body.