[4runero]

Hello everyone, I am the owner of a 2010 Toyota 4Runner, Trail, when starting the Check comes on, the OBDII says there is a fault, error:
1.- (Fault in the oxygen sensor heater control circuit) (A/F low 1 Sensor 1)
2.- ECMECT (Engine and ECT)
Could someone explain to me what these error data that the OBDII gives me mean. Could it be a problem with the Magnaflow manifolds, the catalyst probe emulator?.

[flyrv9]

A little research shows that OBDII should be posting a P0031 code. It means either a bad O2 sensor or problem in the heater circuit. There should be an O2 sensor on each side of the cat convertor; so there may be 4 of them if you have a cat for each bank of the engine. Part of the code tells which sensor it is.

The upstream sensor measures the exhaust gas and compares it to the downstream sensor via the computer. I'm not familiar with a heater circuit; but O2 sensor failures are a common problem. They are easy to change if you have the right socket (it has a slot down the side to prevent damage to the wire). The code and description should point you to which of the sensors is failing.

Also - if you don't have one, an OBDII code reader would be helpful for this and any future issues. You can get basic ones pretty cheap; all the way up to fancy ones that provide all sorts of detail. I got one when I got my 2000 Tundra and it has saved me many times. I've changed 3 O2 sensors and the reader told me which one was failing.