P0133 and P0139 OBD2 Codes in 2001 Kia Optima: Diagnosis and Repair Tips
Hi, I'm new to car diagnostics but am desperate for a solution. I have a 2001 Kia Optima, and every time the check engine light comes on, I get codes P0133 and P0-139. The vehicle runs roughly, stalls at idle, and lacks acceleration response. After spending over $1000 on previous repairs—most recently replacing the speed sensor—the issue keeps returning. I'm now on a fixed income and can't afford further expenses. Can anyone provide clear guidance on what might be causing these codes? Any advice would be greatly appreciated.
The P0133 and P0139 codes indicate issues with the oxygen sensors on Bank 1. Given your recent repair of the speed sensor, it's possible that wiring or connections were left loose during installation. I recommend checking all circuits to the oxygen sensors, especially since repairs in close proximity can introduce errors. A faulty wiring harness or a worn-out oxygen sensor could also be contributing factors. A thorough inspection of the sensor connections and harness integrity is advised.