From what you've given, the error is in your last field.
shutoff = '".$shutoff."',";
ends with a comma
Unless the where clause is missing, it's still an error though
shutoff = '".$shutoff."', where record_id=23456;
shutoff = '".$shutoff."' where record_id=23456;
If not, without a where this will update all records in the database. Not good, that's a big mistake . . .
Otherwise you probably have a quote in the input (?)