Secondary O2 sensor heater current
 

I've been reading over the wiring diagram found here trying to determine if I can power a wideband O2 sensor directly from the secondary o2 sensor plug. I know there's +12V and ground at the connector (in addition to signal and signal ground) but does the ECU control the 12V heater circuit at all? Or does it just sense the current to determine if the sensor is missing or has a bad heater? If it's just a passive "sensing" of the current, and the circuit can handle 3A max current, then I should be able to power my wideband directly. I should point out, I will be running catless headers so the rear o2 will be disabled anyway and my plan is to run the 0-5V linear signal to the o2 signal for Ecutek to read. I'm just trying to see if I can pull it off with a single connector or if I need to run power and add a dummy load resistor to "fool" the stock ecu into thinking the sensor is still there.

Has anyone tried anything like this? Anyone know the max heater current allowed by the ECU?
-Matt

https://www.google.co.uk/search?q=si...hrome&ie=UTF-8

I seem to vaguely remember that for it to work you want a non-ECU ground otherwise you can get odd readings. If you're doing that you may as well wire in a switched 12V rather than try and get it off the existing plug.

I don't know but i can give u this.
This is a maintenance manual for determine it is working good.
wideband O2 sensor and Secondary O2 sensor is different.
But i guess 1 is cathode 3 is anode ,the 2 and 4 just for feedback , it just my guess .
So i think u can made 2 resistance in 2 and 4 to "fool" the ecu and power for your new O2 use 1 and 3.