Hi Richard
L is a hydraulic fault and 221 is a faulty tilt pot,
If you check the pot you may find the plug has got a poor connection in it(dependant on the year)the earlier models had a non waterproof plug and can get moisture in.Just unplug it and give it a good clean with electric cleaner.

You can not get the early type pots they are no longer available if you order a new one it comes as a kit to convert.

If the plug checks out then check the wiring if all seems ok and the linkages are not worn then you may need a new pot,but you may need a laptop to set it up.
Hope this helps
Herald.