It's used for spark timing, I think. But it depends on the year of your car. If your MX6 is a 93 or 04 it will use the NE1 sensor (in the distributor) if code 02 is present, and will still run (though not as well). But a 95 or later car does not have a NE1 sensor, and will not run when code 02 is present.
First check the connector to the crank position sensor (down behind the oil dipstick). It's a known weak spot, because water gets in there.
The crank position sensor should have between 520 to 580 ohms resistance.