Hi all, My check engine light is on, and it is about air/fuel sensor. I am trying to remove the old a/f sensor, but it is too tight. I am even not sure if I wrench the right place. Could you help me to check, if I should wrench the red place, or blue place? Is there any way to save some energy? Thanks

 

I just replaced my Bank 2 sensor. First, if you are sure your sensor is kaput, cut off the wires. Get yourself a good 6 point 22 mm deep socket and breaker bar. Forget about the special O2 sensor sockets because they flex. You can use an adjustable wrench when you install the new one because they do not require much torque. Wrench the red. Apply PB blaster a few times per day for several days before removal. Chances are it will come out easily without doing everything I suggest. However, if you get a tough one and round off the sensor nut, you are royally screwed. Trust me, I speak from experience.

 

I hope you have the new sensor at hand. Examine it and you will know which face(s) the wrench should fit. I prefer a box wrench as the connector can pass through. For bank1 sensor which is accessed from below, an offset box wrench is needed. For the one you are trying to reach a standard box wrench should work.

Soak it and let it sit. Soak it again and then apply force. Once you budge it, remember 1/8 forward 1/16 back, 1/4 forward, 1/8 back, 1/2 forward, 1/4 back and so on. Shoot some more pb once the threads expose.

Salim

PS: I would highly recommend buying a OEM sensor.

 

A little heat sometimes helps the pb blaster along. Spray it (area between the red and the manifold), then let warm the car up to temp with a quick drive around the block and spray again. A big long handle 22mm box wrench comes handy too, if you don't have access to a good 6 pt 22mm deep socket and breaker bar. Slip a pipe or jack handle over the wrench if you need extra leverage to break it loose.

 

If you have to ask where to put the wrench, you should take it to a professional. My advise.. once you figure out there's no where to put a wrench on the blue area.. if it starts coming out hard, take it somewhere. The sensor is seized and you'll end up tapping the manifold. I've done it a bunch of times.