So, I've not fully delved into the Honda engine management yet, but for the most part what I'm about to say applies to all sequential fuel injection.
There's a cam sensor and a crank sensor. Sometimes called a crank angle sensor, or crank position sensor.
Anyway they're almost always a simple hall effect sensor, reading notches in the flywheel/flexplate and a wheel timed to the cam. The ECU uses the two sgnals to determine the position of the crank, and using the information from the cam, to know when cylinder #1 is TDC on the ignition stroke. That's how the ECU "knows" where the pistons are and when to fire the ignition coil/injectors. usually when the CAM sensor goes it will limp, basically the ECU will take a guess as to where the piston is and keep trying to guess until the motor fires. You will experience longer than usual cranking times as the computer guesses.
When the CRANK sensor fails you will get a no start condition, because the ECU has no clue where the pistons are.
This is what the harness looks like:
It's $119 bucks at rockauto and listed under "CPS" in the ignition section. It looks like a massive PITA to change, but then they usually are because of where they must be located to get the data needed.
Quick fixes when you're dead on the side of the road:
unplug the connector that someone has illustrated and short the CPS side of the harness with a piece of wire. It will usually make them work again. If you want to troubleshoot it, use a multimeter and measure the resistance cold and hot. if it wigs out when it's hot (and that's when your no start/stumble is) then the sensor is failing and it WILL leave you stranded eventually.
Like I said, this was a generalization, but for the most part 90% of multiport fuel injections systems work like this, and from what little I've researched the Honda engine management it does as well.
