Hello fellows,

I have a recurring P0133. I can't seem to pinpoint what triggers it.
I'll get the code, clear it, and it won't come back for weeks, but then it will show up again - only thrown once, MIL on.

Actron lists the code to mean :
O2 Sensor CKT Slow Response (Bank 1 Sensor 1)

The one thing I can gleam from the freeze frame data is that the engine load percentage is usually low when this is thrown, ~10%.

I know this points to something wrong with the signal from the front O2 sensor, but does anyone actually have any experience with this code recurring this fashion and/or what it might mean? what might cause it?

I know the easy first thing to try would be to replace the O2 sensor, but I'm pretty sure it was replaced at a Volvo indy I bought it from. I also happen to know that this guy doesn't like using generic O2 sensors, though I guess that doesn't guarantee that he didn't use one this time...

The car gets fine gas mileage and has lots of power and otherwise seems to work great.

Any and all ideas are welcome.


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1998 V70 AWD Turbo 190k+