A novel method for designing t-UED and BUED code checkers is presented. In particular we consider Borden codes for t = 2k - 1, Bose and Bose-Lin codes. The design technique for all three checker types is mainly based on averaging weights and check symbol values of the code words. The checkers have a simple and regular structure that does not depend on the set of code words that is provided by the circuit under check. The checkers are very well suited for use as embedded checkers since they are self-testing with respect to single stuck-at faults and almost all combinational faults in a single cell under very weak assumptions. All three checker types can be tested with only 2 or 3 code words.