As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#1 ENGINE CONTROL LIGHT ILLUMINATED PRIOR TO TAKEOFF. GROUNDED - YES. PERFORMED EEC BITE TEST ON #1 ENGINE. FOUND FAULT 75-20581. ACCOMPLISHED B737-800 FIM TASK 75-23 TASK 801, AND GROUND RAN ENGINE. EEC CONTROL LIGHT REMAINED EXTINGUISHED. FAULT DID NOT RETURN.