I have a vw polo 2001 and i am having to replace the lambda sensor. Was wondering where abouts under the car it will be?? and is there different varieties of lambda sensor? if so which do i get?
This might not specifically answer your question, but are you sure you need to replace the lambda sensor? My vw golf reported interim problems from the lambda sensor, but found out that actually the fault was caused by a faulty spark plug cable.
The sensor measures the oxygen mix into fuel, roughly, and the fault tripped due to the spark plug not firing in time which messed up the sync.
trace the exhaust from under the engine to the front, behind the grille. there should be a can shape just before the exhaust enters the engine the sensor is screwed into the top of this can. you may need to take off the bumper to get proper access to the O2 sensor. use a vacuum cleaner nozzle to clean out the cat while you have the sensor out. do a search on e bay for the O2 lambda sensor for 01 polo to make sure you have the right one
The sensor is normally found on the exhaust soon after it comes out the engine or just after the catalytic convertor. It looks like a spark plug with a couple of wires coming out the top. Simply unplug the wire and unscrew the sensor with a spanner, it may need a bit of heat to loosen it up or you might get it undone without. Replace with new lamda sensor, which should come with a washer, and plug back in. /be careful though if you have used the car because all the exhaust components including said sensor will be bloody hot!!
you could come unstuck doing this , they seize in and may need heat and a special socket for the job, there is only one sensor, that controls the emissions