Engine will not crank over?

Because battery voltage is low and belt tensioner looses belt tension so the belt slips. If you can jump it and it starts it's probably anti theft engaged look online to reset

If you get a test light to light at the where arrows are in pic then it's not the pcm it's either bad contact at relay or the yellow wire leading to starter is shorted oryou'll need to get it scanned. I have no further comments nor suggestions.

The cam and crank sensors have nothing to do with cranking the engine. They are for fuel injector and spark timing and to turn on the automatic shutdown (ASD) relay. When you install a new crank sensor, there will be a thin plastic rib if it's an aftermarket sensor, or a thick paper spacer on the end to set the critical air gap. If you reinstall a used one, you are to cut off the remaining part of the rib is there is one, and use a new paper spacer. If you don't use some type of spacer, the sensor could hit the ring on the flywheel and be broken.

Do you hear the starter relay click or do you hear a single kind of loud clunk from the starter each time you turn the ignition switch to "crank"?

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Just so we don't overlook something stupid, you are pushing the clutch pedal down, right?

An easy place to start is with the starter relay. One plan of attack is to remove its cover and squeeze the contact. If it cranks, you know the high-current circuit to the starter and the medium-current circuit to the solenoid are good. That just leaves the low-current circuit from the ignition switch.

A second method involves making four tests in the relay socket with a test light. Ground the test light to the battery negative post, then probe the four terminals in the socket. Disregard the unused fifth one in the middle. One must have 12 volts all the time. One must have 12 volts only when the clutch is pressed and the ignition switch is in the "crank" position.

Next, move the clip lead to the positive battery post and probe the two remaining terminals. The test light must light up on both of them indicating a good circuit to ground. One is for the relay's coil and would include the neutral safety switch on automatics, and one is through the starter solenoid.

If you don't find any voltage on one terminal in the crank position, measure on the clutch switch under the dash. If you have it on one side but not the other terminal, jump the switch to prove it's defective. If you don't find voltage on either terminal when turning the ignition switch to "crank", suspect a broken cam on the end of the switch cylinder. It will turn the switch far enough for the dash lights to turn on but not quite far enough to hit the "crank" contact. The dealer's parts department has a repair kit for that.

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