on March 19, 2011, 8:39 pm, in reply to "Re: Seat Leon - MOT Emission Failure + EML Illuminated"
You could also test with a meter that measures duty cycle. The last one of these I played around with had a duty cycle to S1 of about 58% (which is correct according to AD) and S2 (narrow band) was about 10% but I was not able to confirm if that was correct or not. If you want to use the scope set it for about 20V/250ms.
From reading your original post again I see that you have batt volts to at least one of the terminals but I think you need to confirm whether that is the heater supply or not. As I have said, it seems odd that codes point to both heater elements and the only thing common is the supply. Another question is, is the ecm going into closed loop? If it's not happy with the heater circuit it may not.
Dave,
I have just tried searching for an excellent thread on testing O2 heaters which I think you were involved in. I think that that thread would help Pete if you are able to find it.
Regards, Bryan.
