As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT TAI AMBER LT ON ENGINE DISPLAY CAME ON ITER MD ON CLIMB ENG ANTI ICE SWITCH WAS OFF AND COWL BLUE STATUS LIGHTS WERE EXTINGUISHED TAI AMBER LIGHT WENT OUT AT 9 C ON TAT NOTE APU CONTINUES OPS WITH BLEED SWITCH OFF. GROUNDED - YES. REMOVED AND REPLACED #1 ENG TAI VALVE REF B737-800 AMM 30-21-11 OPS CHECKS GOOD NO AMBER LIGHT CAME ON.