I find it ironic that nearly all your replys to other techs ask for all four gas readings even if it is a rear wheel bearing fault, but on your post about an emiissions failure you only give us snippets from the gas analyser.
Appologies if you feel I am taking a pop but it did make me chuckle.
Anyhow to the subject in hand. I am surprised to read you have never come across the term Pulse width modulation before, as for many years now the VMs have used this method of controlling actuators and solenoids in allsorts of applications.
Turbo boost control, EGR control, intake butterfly control to name a few.
Dave Hill puts it very well in his desription further up , I would not say he has over simplified it more put it into a nice easy to understand way without complications such as resitance and temperature. There are some things you don't need to know so why complicate it..
Personally I agree with you that you need to sort the problem with the heater circuit before doing any further testing on this vehicle and from what I have read in your other posts you are not out of your depth with this one but you seem to have taken a knock to your confidence and just need a shove in the right direction.
Forget testing this sensors signals with a voltmeter as that will not reveal much of any use, these sensors generate very low current which is monitored by the ECU and can only realy be veiwed on a scope if you have a very expensive clamp like the one in the piccy below. Confirm integrity of the wiring to the sensor and test the heater circuit the same as you would on a 4 wire std sensor bearing in mind the PWM. A scope and a low amps current clamp is usually best for this.
Use livedata to evaluate sensor operation group 30 upwards, group 33 gives a represntative display of the sensors output in block 1 & 2.
It wouldn't surprise me if the new o2 sensor is faulty though, I always fit Bosch if OE or Genuine from TPS,
HTH,
Mike
M.O.M. Miserable Old Manc
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