As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START #1 ENGINE COWL VALVE OPEN LIGHT REMAINED BRIGHT BLUE AFTER SELECTING ENG ANTI-ICE ON. TAI INDICATION ON # 1 N1 GAUGE REMAINED AMBER. GROUNDED - YES. PERFORMED B737-900 FIM 30-21 TASK 805, FOUND ENG #1 COWL TAI VALVE PERFORMING NORMAL. PERFORMED ENG IDLE RUN AS AN EXTRA PRECAUTIONARY MEASURE, ENG #1 COWL TAI VALVE PERFORMED NORMAL.