oxygen sensor hot when car hasn't been started?

[Jackel]

Howdy peoples,

Just noticed today when cleaning my engine bay that the oxygen sensor is boiling hot but the car hasn't been started in 24 hours. Everything else around it is cold. I don't believe it should be like that and if not anyone know what is causing it?.

Thanks

[willwal98]

my guess would be it's a heated sensor. It should only heat when the ignition is on so if it's hot all the time you've got electrical issues. Maybe got some water somewhere causing a short?

[Jackel]

That could be it, I was playing music. Do you know does it have to be on the "on" or accessories for it to work because i just had it turned to the first one.

[The Real Roadrunner]

should only heat up with ign on, unless somone has done a bodge wiring job etc.
it wont overheat but it will drain a battery and probly shorten the life of the heater.

cheers
linden

[Jackel]

I have cut and extended the wiring for the oxygen sensor because it was the short since i change dumps, maybe i could have got the wrong black wires mixed up. Does anyone know what would happen if they were mixed up?

[GT1978]

Read through this thread and check your wire colours accordingly.
Rewiring oxy sensor

Don't think there will be any problem with the sensor heater being wired wrong. Would just run the heater longer maybe shortening it life. Would be more concerned with what is running the sensor heater. I would think there shouldn't be any power on any of the sensor wires when the ignition is only on acc. However the heater may have a constant +ve and be grounded to switch on by ecu in which case the heater ground may be connected to the signal reference ground in which case it could be running constantly and may affect the accuracy of the signal.

Anyway recheck the wiring and keep an eye on your battery.

Glen

[Jackel]

cool say two black ones are identical so guessing i just gotta make sure they are still wired together but pretty sure now its heated on purpose.

Thanks all !

[thechuckster]

3 & 4 wire O2 sensors are heated.

keeping it warm wont hurt it, just will drain your battery if you leave it one for hours.

narrow band sensor do not use the heater supply for any reference - you just wont get a proper reading until they're up to temperature.

If you have a wideband O2 sensor (which a stock sensor isn't), you will do some damage if you have it in zorst gasses (e.g. engine running) but the sensor & controller not powered up.

[Jackel]

this is the stock 1ggte sensor it was two black wires and one blue in the other post it said the two black ones are the same thing.

[oldcorollas]

yup, two black wires are heater and ground for heater.. blue is signal wire, and the signal earth is thru the exhaust..

put multimeter on both black wires, and see if they get power at ACC or IGN... alternatively, have the power for the ECU trigger a relay for the O2 sensor heater power.