TechHelp2, or anyone else knowledgeable, not wanting to revive a 6-year-old thread, I quoted the other thread below...
My wife's Caravan seems like it's not getting enough voltage to the starter solenoid. Usually it will grind against the flexplate, failing to engage. About every 2nd or 3rd attempt it will actually engage and start. Obviously I'm not wanting this grinding but I'm struggling to figure out what's wrong. One of the few times it started I drove over to the AdvanceAuto and did a battery/starter check. Everything checked fine except there was a slight parasitic drain. I've pulled the battery and had it checked separately, it's fine. I read what you posted in this other thread and I find that there is NO continuity to ground at the cavity for relay terminal 85.
I've bench tested the starter, and had it tested at Advance and O'Reilly, they say the starter is fine.
Next question is, how do I check the transmission range sensor? I guess I'm looking for which leads on the connector to test? Any help is certainly appreciated.
Note: The battery is disconnected while I'm doing this.
I found this information on the AllData Website. See if this helps you out.....
The coil ground terminal (85) is connected to the electromagnet in the relay It is grounded through the transmission range sensor only when the gearshift selector lever is in the Park or Neutral positions. Check for continuity to ground at the cavity for relay terminal 85. If not OK with an automatic transmission, check for an open or short circuit to the transmission range sensor and repair. It is grounded by the PCM if the conditions are right to start the car. For automatic transmission cars, the PCM must see Park Neutral switch and near zero engine rpm. For manual trans. cars the PCM only needs to see near zero engine rpm. Check for continuity to ground while the ignition switch is in the start position. If not OK and the vehicle has an automatic trans. verify Park Neutral switch operation. If that checks OK check for continuity between PCM and the terminal 85. Repair open circuit as required. If OK, the PCM may be defective...
I failed to mention that this is a 4-cylinder engine.
If you are relating this post to the problem you are having then you are looking in the wrong area.
If you starter is engaging but grinding (as stated in the post) then it sounds like the system is working properly and you need to look at the condition of the flywheel (Flex plate).
You may have a flat spot on some teeth of the flywheel (Flex plate) that when it matches up with the starter gear it grinds until it gets past the spot then it will start.
Remove the starter and turn the engine slowly by hand (with the battery disconnected) and inspect every tooth on the flywheel (flex plate). You will probably see the ground out teeth eventually.