Originally Posted by das_peikko
No access to live data. The original MAP sensor that had an intermittent problem was caught by an oscilloscope. The oscilloscope was able to map out super fast variations in voltage changes. The volt meter shows the 3rd digit to the right of the decimal changing too fast to see. Your theory of secondary ignition noise disrupting the ground flow back to the PCM is interesting.
The PCM sends out a resisted ground bias on the MAP signal circuit to suppress noise, The resistance to ground is high enough that it won't affect any hard voltages produced by the sensor.
Not much need for a scope for this, Just make sure the PCM is receiving MAP voltage & wiggle the wiring at the MAP sensor while watching the MAP voltage PID to confirm you don't have a intermittent open or short to ground! However......We all have our ways of doing things!
IIRC....The set criteria for P0107 is voltage below .02 vdc which equates to a intermittent open, short to ground, Or a shorted sensor.