91 MR2turbo code43 - Toyota Nation Forum : Toyota Car and Truck Forums

***Tercel GTS*** · 09-27-2003, 04:47 PM

I get a code43, the diagnostic book says O2sensor heater. Is that the same as the O2 sensor, or a seperate part all together?
Any help greatly appreciated.

OEMonkey · 10-12-2003, 12:29 PM

It's part of it. 4 wire o2s have the heater. These have an internal heating element that allows the sensor to reach operating temps. quicker and maintain it during periods of idling or low load. Your o2s is your main input during closed loop, for it to be in closed loop it has to be a certain temp.
There is a resistance test you can do to see if the heaters good. You'll need to disconnect it at the connector and use an ohmmeter. Consult your BGB for specs.