Sensor Ground

Hi there. My name is Jesper, writing from Scandinavia. I been following the scannerdanner videos for 2-3 years now.
I am an owner of an old Chrysler PT cruiser 01. I work as an Mercedes tech for 22 years now.
I have a lot of hesitation and jerking in decel in my car, around 1800 rpm and Falling. I can see that the injectors is beginning to fire around that time, but only on 3 cyl. it is not the same cyl missing every time, looks on the pico like it is computer controlled. actually it loks right, but I doubt. no need to fire at 1800 rpm I think. I measured my sensor ground with a scope from the iat (bk/bu) and the ground lead to bat. neg. I saw spikes of around 500-600 mv (looks like it is coming from the injectors, only when I am accelérating), and current ramping and a lot of other signal. If I measure the sensor ground with a dvom, it only says 70 mv and that is ok. My question is, is that normal, to messure such things with a scope on the sensorground and 2, isn´t it a job for the noise suppressor on the cyl. head to take care of??


Best Jesper.

Keep up the good work over there:-)

Hi Jesper,
I don't have an answer to your question but wondered, since you're a Mercedes tech, if you might be able to shed a little light on an 06 CLS55 AMG w/supercharged 5.5L I've been struggling with:

www.scannerdanner.com/forum/post-your-re...o2-sensor-codes.html

Thanks and hopefully someone will be able to answer your question.

John