Testing O2 sensors

L

Lower

Member
Anyone know how i can test the O2 sensors on the car?

I have stutter around the 2k rpm mark that i can't seem to get to the bottom of. There are no fault codes logged, I've replaced the MAF which has had no effect and i've replaced coil packs with no effect. However, when the adaptions/trims were reset at the inspection 1 the fault was completely cured. However, as the miles have gone on and the fuel trims have started to adjust again the stutter is starting to reappear.

This makes me think that there is a sensor on the way out (but not failed) which is feeding the ecu with duff info which is causing it to adjust the fuel trims which gives the stutter. Most likely culprit would be a O2 sensor.

So, can i check the operation of the O2 sensors? I've been able to on previous cars by checking the output voltage and the number of pulses per second.
 
Just from guessing the meaning of these codes don't O2 sensors warn you if they are failing?

271F Lambda sensor period duration ageing
2720 Lambda sensor ageing TV
2721 Lambda sensor ageing after cat
2722 Oxygen sensor2 before cat.
2723 output heater O2-sensor before catalystbank2
2724 Oxygen sensor2 after cat.
2725 Lambda sensor periode duration ageingbank2
2726 Lambda sensor ageing TV bank2
2727 Lambda sensor ageing after cat bank2
2CA2 heating lambda sensor of front cat
(shearing stress)
 
O2 sensors can start to give out the wrong signals even though the parameters they produce are within the tolerances that the ecu views as healthy.

i really want to be able to test the output of each o2 sensor and compare it against the the other comparable sensor to check that the outputs are similar. I suspect that one of them is giving the wrong output and the ecu is gradually adjusting the fuel trims to try to compensate which is what is causing the poor running.
 
I understood. It sounds like a possible diagnosis.
Asking Bosch for advice would be my first step.
I don't think they will be helpful though.

Wouldn't it be much easier to swap in a new sensor?
 
The last o2 sensor i checked was on a Toyota MR2 turbo and was pretty straight forward(though quite a few years ago). Checking the sensor involved measuring the voltage it produced and counting the number of pulses per minute but that was a narrow band o2 sensor.

It may not be possible with the Z4M sensor, but i'd like to know before i start changing components at random. I've already changed the MAF sensor and the coil packs unnecessarily so i'd like to know if the O2 sensors are genuinely faulty before replacement.
 
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