Retrieving codes from the OBD on a 1995 Pontiac Bonneville SSEI


The check engine light is on? AutoZone attempted to scan for codes using a OBD II scanner. The result was that the scanner said that it could not enter the system, therefore, no codes were retrieved. Is my car equipped with OBD I, OBD I and 1/2 or OBD II? If it is not equipped with OBD II, how do I read the codes to find out the problem? Is there a way to retrieve the codes without using a scanner?