P0133 Code on 2011 Kia Soul... troubleshooting advice?

I’m dealing with a P0133 code (slow response on oxygen sensor) on my 2011 Kia Soul. I’ve already replaced the oxygen sensor and the catalytic converter, and I’ve checked the fuses, but I’m still getting the code. Anyone have tips on how to further troubleshoot this?

P0133 usually means the sensor is detecting slow switching. Have you checked for any exhaust leaks? Even small ones can mess with the readings.

Mary said:
P0133 usually means the sensor is detecting slow switching. Have you checked for any exhaust leaks? Even small ones can mess with the readings.

I haven’t thought about checking for leaks. I’ll give that a try.

Make sure there’s no damage to the wiring or connectors for the oxygen sensor. Sometimes the issue can be a bad connection rather than the sensor itself.

Kimberly said:
Make sure there’s no damage to the wiring or connectors for the oxygen sensor. Sometimes the issue can be a bad connection rather than the sensor itself.

Good point. I’ll double-check the wiring just to be sure.

Since you’ve already replaced the sensor and cat, it might be worth testing the sensor voltage with a scan tool while the engine is running. If the readings are slow, it could point to another issue upstream.

@SophyGenesis
I do have a scan tool. I’ll monitor the voltage and see if anything looks off.

I had a similar problem once. Ended up being a faulty mass air flow sensor causing the O2 sensor to read wrong. Might be worth looking into.

Lilyharper said:
I had a similar problem once. Ended up being a faulty mass air flow sensor causing the O2 sensor to read wrong. Might be worth looking into.

Interesting, I hadn’t considered the MAF sensor. I’ll check that too.

Mike V. shared a service manual link for troubleshooting Kia DTCs. You can check it here. It might have some more detailed steps for testing this code.

@Brynn
Thanks for sharing that link. I’ll check it out and see if it helps.