why is there no board exam for computer engineering?

Answer 1

Are you referring to PE boards?

PE licensure is specifically to ensure that the engineering work performed by PEs will not hamr the public. However, most states have an industrial exemption, so that if you work for a large company, there is no need for PE license.

This is particularly true of computer engineering, since their products tend to be extremely expensive and not funded through a contract with a public customer.