2006 Caravan 3.3L.

Starter clicks once (strongly) but won't crank. It does this consistently every time I turn the key. First I hear the relay come on when I turn the key to on, then the starter engages/clicks and that's it... no action beyond that. When the PCM fails, does it create this symptom? Or will it prevent he starter form getting power altogether, not even allowing it to click?

 

If it is indeed the starter solenoid or relay that is clicking then the PCM is doing it's job at least in that respect. They won't click unless the PCM supplies a ground to the starter relay coil.

You probably have worn solenoid contacts in the starter. Next time the starter just clicks tap it with a hammer. If it comes alive you just proved it. Or check for 12vdc at the starter solenoid connection on the starter with the key turned to start. If it's there change the contacts or for twice the price change the starter.

 

You can be tricked by clicking sounds, so don't count on it being the starter relay or starter solenoid you're hearing. The only thing that can prove that they are getting voltage to the starter motor and solenoid is a voltmeter and a conventional needle multimeter is by far the best tool. My problem was intermittent. I wasted money on a new starter that I never wound up not installing because two spare fobiks I got days later caused the problem to go away. The starter sits unused.

To clarify, my 08 had same no crank symptom with engine compartment clicks and it was NOT the starter. When turning the key switch, a number of accessories are activated resulting in clicking sounds. A voltmeter proved my starter solenoid never got solenoid voltage when it failed to crank, but I heard clicks. An 06 can produce clicks with no solenoid voltage too.

By the way, my problem was corrected by a new fobik, so that won't be your problem because your van uses conventional key.

Summary:

First verify that CONSTANT +12 voltage is being sent to your starter solenoid thru the control wire when you turn the ignition switch to crank position and get a no crank condition. If voltage is present, then the starter is BAD assuming the two tests below PASS.

Next, verify Battery + AND - power circuits to starter motor:

1) The voltage from the + battery post to the starter lug should show only a couple tenths drop when the ignition switch is in the crank position. Low voltage drop proves the positive power lead to the starter is good.


2)The voltage from the engine block to the negative battery lug should only be a couple tenths when the iginition switch is in the start position. Low voltage drop proves the ground strap to the engine is good and capable of carrying load. The ground strap on Gen 4 is usually on the top starter bolt. They are known to corrode off or break, so the engine block floats above ground. In this case the starter motor will NOT get the necessary battery voltage to crank. See youtube videos on the subject.

PS: a number of problems can cause no voltage to reach the starter solenoid. The PCM is only one possibility. There is also a starter relay that can fail and the transmission park position interlock switch can go out of adjustment or fail. There are youtube videos on this topic too. I would surely not be changing the PCM until ruling out all other cheaper troubles lol.