On a recent long trip, I blew out the resonator on my 2000 Maxima. I got to a Midas shop where I had it replaced. Soon after (on the return trip) I started getting a consistent P0141 code (O2 Sensor Heater Circuit Malfunction) which points to the downstream unit, which just happens to be close to that resonator. There doesn’t appear to be any damage to the wiring that I can see, and I can’t find any blown fuse that might have disabled the heater. I’m reluctant to chalk this one up to coincidence, although I doubt that the heat from the welding could have affected something this close to the catalytic converter. Should I just bite the bullet and replace it?
It’s possible that welding in such proximity to the sensor may have damaged it, if the ground clamp for the welder was placed on the other side of the sensor from where the welding was done. It’s possible that driving with a blown resonator may have damaged the O2 sensor–pulses of cold outside air alternating with pulses of hot exhaust hitting the sensor element. It’s possible that the sensor just failed because it’s 12 years old.
Check the sensor heater element for being open circuit, or just replace it. I don’t think those are too hard to reach, if I remember correctly.
I would have the code reset and drive the vehicle. If it comes back then replace the 02 sensor. The code may have been set erroneously when the resonator blew out. It happens.
I should have mentioned: I did clear the code and it did return. Ordering a replacement as we speak. Thanks, guys!!