Nice job! Those aftermarket O2 sensors might not be the best buy. Some cars are very picky about it being the OE sensor. I’m not saying they won’t work but they could be a problem. Thanks! I agree that the aftermarket sensor is a risk - I figured I'd take a shot and it's been working fine for a cou...

So I finally finished all the catalytic converter refreshes this car needed, and posted a brief "cinematic" summary video on YouTube.

Hopefully this will be helpful as this seems to be a common failure point in this vintage of car!

What tool did you use to make this photos? (with temperature) I used a FLIR thermal camera. I have one for industrial applications, but you can now get fairly cheap units that work in conjunction with a smartphone. If you search on Amazon or similar you will find many models. None of them are dirt ...

If anyone wonders what a 3.2 XC90 sounds like with no muffler, here it is:

I pulled the whole exhaust out for inspection and cleaning: IMG_1786.jpeg These remaining sections are a lot easier to remove than the converter, although I broke a screw off removing the middle support bracket (which was also very rusty): IMG_1784.jpeg I will try to replace the support bracket, or ...

I did some bench-top testing of the two O2 sensors, and it looks like the heater isn't working on the rear bank 1 sensor (the one flagged in VIDA). Here's a thermal image of the "good" sensor, with the heater leads hooked up to a power supply at around 12V: IMG_1778.JPG After a couple of m...

Here is a closer view of one of the O2 sensors, showing the part number: IMG_1768.jpeg Apparently the gap between the corrugated upper cladding and the lower cylinder is where atmospheric O2 is allowed to enter. Denso has some good information on troubleshooting O2 sensor codes. . In my case, the re...

The front catalytic elements still seem fairly clean:

Although I'm not completely sure how a degraded converter would present.

I spent the afternoon pulling out the converter assembly. Support bracket had rusted out again, and the thinner sections of exhaust pipe were failing or on the verge of failure: IMG_1763.jpeg I managed to get both O2 sensors out (penetrating oil and impact gun): IMG_1765.jpeg I was careful not to ke...

Fast forward to 2022, and my repairs are starting to leak again. I'm also getting the following codes related to my rear O2 sensor in Bank 1: ECM-P013700 02 Circuit Low Voltage (Bank 1, Sensor 2) ECM-P227000 02 Sensor Signal Stuck Lean - Bank 1, Sensor 2 I used VIDA to plot the O2 sensor voltages, a...