Our lovely 01V70 keeps throwing a P0032 code which our reader says is bank 1 sensor 1 high circuit heater. So.. high what I assume current. I just replaced the sensor with a Bosch without the factory plug, used that funky connector thing, then took it out and butt connected all the wires.

I then measured the voltage of the heater circuit with the O2S plugged in after I measured the resistance of the heater (around 5 ohms). started the car the voltage goes up to 13.8, stays for about 5sec., drops to 0 then goes back up to 13.8 for about a sec. Seems like the ECU is detecting over current and shutting it down. I check resistance back to the ECU and see 30k ohms. so no short in the wiring.

So I start thinking maybe I have the wrong sensor and it's overloading the ECU driver (which seems like just a sinking open collector)so I hook a 30ohm 2watt resistor, followed by a 500 ohm and have the same results with all. So with 500 ohms the driver would only have to source about 30ma.

Seems like an ECU issue to me but I'd love some advise otherwise????

Thanks

 

I would install a direct replacement sensor. Volvo's HATE generic sensors!