As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX FLIGHT NR 21568 - ON TAXI NOTICED A PITOT HEAT 2 CAUTION LIGHT, CHECKED CIRCUIT BREAKER AND NOTICED IT POPPED ON PANEL 2. TAXIED BACK TO GATE. MAINTENANCE RESET CIRCUIT BREAKER. OPERATIONAL CHECK GOOD. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.