What do codes 12 or 71 on a 1990 Geo Prizm when the check engine light is on?

1990 GEO PRIZM code 12 = RPM Signal Distributor, distributor circuit,starter signal circuit, igniter circuit igniter, ECM 1990 GEO PRIZM code 71 = EGR EGR system including hoses,gas temperature sensor circuit, gas temperature sensor, vacuum switching valve for the EGR circuit, ECM