I have taken out this camshaft position sensor out of my Chevrolet Aveo 2007 and I am trying to verify whether the issue I am facing is with the sensor or the ECU/computer (the car cranks, but does not start and had P0340 code).
My question is - how do I wire up this camshaft position sensor in lab environment (without car in the picture) to verify that it is working according to its specification?
The harness that plugs into sensor has 3 wires (Pink, Black, Black&Blue). When I turn car key to ON position with harness unplugged from sensor, then
- voltage between Battery Minus and Pink Wire slowly grows from 2V to 12.2V over 10 second period;
- voltage between Battery Minus and Black Wire stays at 0V;
- voltage between Battery Minus and Black&Blue Wire stays constant at 5V.
With sensor plugged into car's harness and intercepting with oscilloscope between Black Wire and Pink Wire at the time of Cranking I see that 12.2V voltage disappears and there are "squarish" pulses that don't have steep triggering edge with lows of 0V and peaks at only ~2.5V:
I guess this is confusing me because this sensor does not have a simple Output pin where ADC in car's ECU measures voltage. I am not sure:
- which electrical property (current, voltage) is supposed to change on which wire when camshaft position sensor detects tooth on reluctor ring.
- why voltage on Pink wire slowly grows from 2V to 12V. And when I crank, then oscilloscope shows waves of 2.5V peaks between Black and Pink wire. Was it supposed to be constant at 12V?
- W.R.T. #2 as test would it be safe to connect Battery Plus to sensors pin where Pink wire previously went in to eliminate problem of voltage slowly rising to 12V?
After adding 10KOhm sensor, as suggested in one of the answers by JRE, I see that rising edges in the oscilloscope are now steep. This probably proves that problem in my case is not with the sensor, but rather somewhere else in my car's electrical wiring.