As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT @ FL360 (SAT-55C) IN BOTH SMOOTH AND LIGHT TURN CONDITIONS THE ENGINE #2 COWL VALVE OPEN LIGHT FLICKERED AND THEN MOSTLY STAYED ILLUMINATED BRIGHT BLUE. NO TAI INDICATION NEAR N1 GUAGE OR OTHER ABNORMALS. FOLLOWED QRH PROCEDURE. GROUNDED - YES. UNABLE TO VERIFY FAULTS-COMPLIED WITH TSR STEP 3-REMOVED & REPLACED #2 ENGINE COWL TAI VALVE IAW B737-800 AMM 30-21-11-COMPLIED WITH INSTALLATION TEST-OPS CHECKS NORMAL.