P0031 2003 Toyota Camry 2.4L - power to 02 sensor stops after about 25 seconds

Question

Got p0031 error. Checked o2 sensor and no resistance to heater. Replaced sensor, reset ECM but idiot light and p0031 comes on after about 25 seconds. Checked harness to ECM and it does delivers 12 volts after start up then stops sending voltage after ~25 seconds.

Answer 1

Power to the A /F B+ is constant depending on what wire you are measuring, Being a A/F which is a wide band does time out for the heater, Whether this is a 02 sensor or A/F sensor they are nothing more than a negative coefficient heat sensor,

 

Replace the EFI relay and retest

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