on February 10, 2011, 8:29 pm, in reply to "Re: Ford Focus 1.6 P0135 O2 Heater Circuit reocurring "
"I like Terry's suggestion of scoping the heater circuit from cold and seeing how long the O2 sensor is supplied voltage, I assume when conditions are right the heater circuit is switched off."
I may be wrong but I think Terry is suggesting you check whether the duty cycle is changing as the temp increases? I have also always been under the impression that the heater circuit continues to work, albeit at a lower duty cycle after full operating temp has been reached? Perhaps someone can tell me if that is correct as I have got to look at a VW which also has a heater circuit problem.
Regards to all,
Bryan.
