Hi guys and gals, I got this code P0031 on my 2003 Lexus GS300 and after looking it up, it showed as below:

- Faulty Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1
- Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 harness is open shorted to ground
- Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 circuit poor electrical connection
- Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 circuit fuse
- Faulty Engine Control Module (ECM)

If I replace this sensor, will this fix the problem? Need it done soon for next Smog in 2 months. Thank you.

 

This code lists 5 possible causes. You will have to locate the test procedure (back-probing/voltage/resistance testing) and test the B1S1 to be sure its bad to know if replacing it will correct the issue. Simply replacing the sensor probably is the easiest way to try and correct this issue but is not guaranteed without testing the part first. It is the most likely cause of this issue though in my opinion. .

 

I'll agree most often it turns out to be the sensor, but the best option is to go thru the diagnostics even though 90% of the time it will take you back to the sensor.