As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DUIRNG TAXI OUT AFTER ENG START WE GOT AFT CABIN TEMP, FWD CABIN TEMP , FLT DECK TEMP INOP. CAME ON AND A/C RETURNED TO THE GATE (BTB). MTX GROUNDED ACFT, AND RESET ZONE TEMP CONTROLLER IAW AMM 21-51-13 OPS CK GOOD ACFT REMAINS NO ETOPS. AND RETURNED ACFT TO SERVICE.