Originally Posted by dylanshawley
Uniblurb, I watched your video but did not see a test like I was doing. if I put my meter set on 20k ohms with the black pin on port B and the red pin on port C I don't get any kind of reading my volt meter still reads 1. I can only get a reading on ports B and C if I have the red probe on B and black on C. If it doesn't register anything when I placed them how you recommended would that mean the sensor is completely bad even though it still starts?
The crank sensor test you're doing above is a resistance test with the link to it also in my signature to the left of the video test. And as mentioned in the test you have to put the black probe on the middle B pin (ground cavity) and the red probe on the C pin (power lead/cavity). Your test is reading no-resistance (1), same as the probes aren't touching anything, which means in this application the crank sensor is testing good.
As also mentioned in that test if you reverse the probes you will get some wonky readings which you cannot go by. It would make sense to have the black probe attached to the ground cavity (B) and red probe on power (C) to do a proper test. Reverse this order and the hall-effect crank sensor with magnet inside just won't test right. This is why you were getting resistance with the probes backwards and you just need to ignore this reading.
This resistance test is not fail-safe even though it's listed in most all ZJ FSM's (factory service manuals). What they were doing in the video was testing to make sure the sensor is getting power while the crank sensor signal is carried through the sensor itself onto the PCM/ECU. Have you meter set to voltage. You do this by pinning the wire, or back-pinning the connector, with the red probe going to the wire connected to the C pin (power) and black probe connected to to the signal wire which leads to the A pin (signal wire). This is where a cheap pair of alligator clips come in handy for going from the probes to the pins. Just don't have the red/black pins/clips touching each other.
Then remove the ADS relay from the PDC and just knock the starter over in clicks using the ignition key. Helps to have 2 people to do this but what you're looking for when your meter will read 5V once in a while. This indicates the crank sensor is working by taking the 5V of power, passing it through the sensor itself, then passing 5V back to the PCM in the form of a signal. You can also turn the crank by hand with the key on to check this and an analog meter may be better for watching the needle jump up to 5V once in a while.