1991 Toyota Camry regarding lights on instrument panel

I recently purchased this vehicle from my neice and the dmv said it had to be smogged the morning of the smog test the check engine light came and and stayed on but previous to this the charge light for the battery and the light for the brake had been on but it would not stay on constantly these to lights would come on for a few minutes and then go off the guy that did the smog test said the check engine light had a code 71 but he did not know what that meant the car otherwise passed the emissions test except the functional check that day on the way home the check engine light went off on its own. Now the other two lights are on again I could use help in finding out the problem because I have to go back for another test and I really need that certificate any help would be appreciated. Thank you