P0135 af sensor?

Hello,

The code: P0135 - A/F Sensor (Sensor 1) Heater Circuit Malfunction.

This is likely due to a bad air fuel ratio sensor / Oxygen sensor before the catalytic converter.

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor
https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Keep in mind that many times the code gets triggered for a different component, which can impact the performance of the sensor. It could be an electrical issue with the sensor not getting proper power, which is when the relay is at fault.

I have attached a step-by-step trouble shooting guide for the code P0135 (look below).

Please let me know if you have any questions.
Thank you.