Section 2 Switch Inputs

This chapter is kicking me in the rear. Because I have a 2005 Chrysler Town & Country 3.8 that I'm dealing with, and I'm trying to decipher the circuit to see if it's ground side or power side switched. The code that I'm dealing with is P0403/P0406. But that's for another room in the forum. I can't understand some of the diagrams showing pull down and pull up switches. can you direct me that a discussion that can help me understand this chapter 2. I don't want to fry my cpm. any direction would be helpful. thanks fellow mechanics.

First off as long as you don't short pins together careful probing with a reasonable quality digital multi-meter set on a VOLTAGE scale or an oscilloscope won't harm a computer input or output.

Usually you can tell is a switched input is pull up or down with an unplugged-plugged test. Unplugged a pull down design will always show the supply voltage on one terminal and should show zero volts (although you may see a floating ghost voltage) on the other. But plugged-in you would expect to see battery supply voltage on both until the solenoid is activated by the computer.

Three terminal Position sensors usually the same as throttle position sensors, 3 pins which are 5v ref, Signal and Ground again you can probe with a multi-meter and check the power and ground

MOROSO321 wrote: This chapter is kicking me in the rear. Because I have a 2005 Chrysler Town & Country 3.8 that I'm dealing with, and I'm trying to decipher the circuit to see if it's ground side or power side switched. The code that I'm dealing with is P0403/P0406. But that's for another room in the forum. I can't understand some of the diagrams showing pull down and pull up switches. can you direct me that a discussion that can help me understand this chapter 2. I don't want to fry my cpm. any direction would be helpful. thanks fellow mechanics.

I have a question. You mentioned "power and ground side switching" which relates to Chapter 3 not Chapter 2. This is very easily mixed up when you are learning this stuff. So maybe this is where you are struggling?
Are you working on an output control circuit or a switch input? It sounds like you are trying to apply switch input material to an output control and you cannot do that.
Thanks! Let us know.