Quote:
Originally Posted by cleatus12r
Just for your information:
A/D counts are a more precise way of measuring the 0-5 volt input to the PCM from the Accelerator Pedal Position (APP) sensor. There are 204 A/D counts per volt of input.
Keep in mind that the APP sensor DOES NOT put out 0 volts, nor does it go all the way to 5 volts. This means that you will never get 0 A/D counts or a full 1023 A/D counts. More like 100 to 918 A/D counts.
For those of you who have this "updated" MFD scale, you might want to take this into account on your MFD map.
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Yup. Keeping the operating range from swinging to either of the voltage rails also allows for diagnostic capabilities. 5v systems are usually 0.5-4.5v operating range. Any signal voltage less than 0.5v is considered shorted to low source (ground), and anything over 4.5 volts is considered shorted to high source (5v or 12v).
Another benefit is that the A/D is usually most accurate in the middle of the range. So by taking either end of the range out of the usable system, the overall accuracy of the operating range is increased slightly.