Question

I got the engine code P0031 on my 2003 Toyota Camry 2.4L. I have replaced the B1/S1 and the ECM and the code returned

Answer 1

Hi there,

The code is for the heater circuit on the bank 1 sensor 1 O2 sensor. This is the first O2 sensor on the exhaust system, in this case it's mounted to the exhaust manifold. Most often the heater wire inside the sensor burns up and the sensor needs to be replaced to resolve the issue.

Answer 2

P0031 Toyota Code - Oxygen Air-Fuel Ratio Sensor Heater Control Circuit Low Bank 1 Sensor 1
Read more: https://www.autocodes.com/p0031_toyota.html