Crank Sensor Waveform Amperage

This looks like a “pull-down design” sensor: diag​.​net/file/f219ainup… ​ The waveform confirms that - the sensor is able to switch; - the PCM* provides a pull-up; thus the signal makes it all the way to the PCM. *hopefully; could be something else if miswired. I expected to see more than only 5mA of current, though, to provide better noise immunity…

I have done a few Hall effect sensors now and that seems to be where they all are at, about 5 mA

I expected to see less current on the signal line. 5ma puts the pull up resistor at 2600 ohms. 4700 or 10,000 are more my experience for such resistors in other electronics.

For short tracks inside modules, no problem… but for something snaking a few feet not far from ignition coils… so had to double-check this up: diag​.​net/file/f5ze7or2y… ​ diag​.​net/file/f4tma8edi… ​

Next time I will be sure to include voltage waveform next to it .

Measuring the current is a fast, non-invasive way to verify signal circuit integrity. For the current to be correct; the voltage and circuit resistance have to also be correct. The drawback is having a current clamp capable of small current measurement and then having a known good value of the current. In the future techs may request a “known good” sensor current instead of ckp/cmp, I…

I will let you know monday

Aemc instruments

Its instructive and cool, but otherwise…. what exactly do you learn from measuring the current when the module is looking at voltage switching; not at current flow. Your tool is how much? $1,000?, and difficult to zero, I'm guessing, based on where the zero point is located. I have never owned or even used a micro-amp probe so maybe I'm just envious :). However, I appreciate your posting it…

I have actually diagnosed a cam sensor using current. 98 Grand Caravan 3.3L. Shop replaced cam sensor and had the same code. Code number I can’t remember but it had to do with cam sensor. I found no voltage in the sensor wire when it was plugged in. Occasionally it would start and run just fine with a good signal pattern and occasionally it would not. When it wouldn’t run right the cam signal…

Outstanding!!! nice work

Forgot to zero it, my apologies 😜

Forgot to zero it, my apologies.