Hi all-

I have a 2004 XC90 with ~130K miles. The CEL came on today and I see the following codes:

P0037 - HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
P0141 - 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0031 - HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
P0140 - 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)

Bank 1 Sensor 2 is the Rear sensor, isn't it? The only thing that's confusing me is the P0031 which talks about Sensor 1.

If it matters, just got a new catalytic converter last fall at around 125K miles, but didn't replace the O2 sensors at that time.

Any suggestions on what to check?

Thanks!

 

Quick follow-up:

On the suggestion of someone on another forum, I checked the O2 Sensor Heater fuse under the hood, and sure enough, it was blown. Does anyone have any suggestions for what could cause this fuse to blow?

Thanks!