Replacing O2 sensors
 

Guys,

How difficult is it to replace the O2 sensors (after cat) and does the exhaust need to come out?

Ciao,

JE

Very easy. Uunplug them in the rear-right angle of the engine bay (near the engine mount), and then unscrew them from the exhaust...the wires are simple to route through.

With the exhaust till on the car??

All up to the exhaust system that's on the car. snap on makes a good wrench to install and remove O2 sensors.

With the stock exhaust it is pretty simple, with it on the car.

With aftermarket exhausts like the one I have, it will be a bit more of a PITA because of the shape of the cats...but still not impossible.

Yes, you can do it with the exhaust still in the car. You need an O2 sensor wrench. It is also a LOT easier if you lower the engine a bit by loosening the rear motor mount bolts a bit.

GL,

Jon

This tool will make it easier for you by far

What socket size are our sensors?

The hex is 22mm. You can not get a socket on the O2 sensor. You need a O2 wrench. or a open end wrench. The wires out of the sensor is what keeps you from using a socket or box end wrench, you just can not get in on with out cutting the wires off.

No need to lower the engine. 7/8" open-ended american works just fine. Count the number of flats you turn to get the sensor out and then pre-twist (backwards) by that number into the replacement wire. That will avoid any stress kinks in the replacement.

I did mine without lowering the engine. However, it took over a week for the scrapes to heal on my hands. Would have been much easier with the engine 1/2" lower.

Heard of gloves!? :)

The space was too tight for my hands WITHOUT gloves.

I have done this twice on my tt and the second time the threading was damaged on the old o2 sensor due to the galvanic corrosion.
If this happens to you need an M18x1.5 tap to cleen the threadings in the exhaust.

02 sensor help out
 

Hey guys if i replace the sensor my self, do you still have too go back in the ecu and reprogram it to the new sensor ? *bit O' confusion*