If you are short of cash (removing the 7" main crankshaft pulley to service or replace the $35 CPS sensor at a shop will cost you at least 2 hours -$75 labor) one other possible way to clean the filings off the rather weak magnet of the CPS sensor is to squirt high pressure water into the crack between the pulley and the engine block from the top/front (forward) edge of the back of the crankshaft pulley-engine block crack downwards, hopefully flushing the filings out.
The CPS and wiring is completely encapsulated and fairly waterproof, but the plastic foreign object protector may make this method of water-flushing to clean the magnet off (without pulley removal) not work at all or not work too well. If the problem is really severe this emergency quick fix may reduce it or buy you a bit of time, in any event the water down there behind the pulley in the crankshaft bearing area will drain out quickly and can't do much harm to anything down there. (psst - the crankshaft pulley is like a centrifuge, it will quickly suck-blow the water out like a spin dry cycle)
This method of flush cleaning the Hall Magnet works on the wheel hubs for the ABS/TCS sensor magnets. The stationary ABS/TCS sensor is on the lower part of (each front) axle block. People usually just replace the whole axle block/bearing/hub and sensor as a single unit, but it is also only "foreign object protected" in the hub/block gap allowing ferrous dust to get in there and foul the sensor's magnet, which cannot be accessed, cleaned, removed or replaced.
Again the sensor and magnet are completely plastic encapsulated, (though the backs of GM harness connectors just have rubber grommets and aren't too water resistant) so water in this area (not on wire-entry backs of connectors) is not much of an issue. YMMV
Always do your utmost to avoid getting water into the back wire-entry points of GM (and all) automotive electrical connectors, at that location they are merely rubber grommet "splash resistant" not "waterproof".
