As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN THE NR 1 ENGINE ANTI-ICE SWITCH WAS MOVED TO THE OFF POSITION, THE NR 1 ENGINE CONTROL VALVE LIGHT REMAINED ILLUMINATED. ACFT GROUNDED. PERFORMED FIM TASK 30-21 TASK 804 E. LIGHT EXTINGUISHED. THIS INDICATES AN INTERMITTENT FAULT WITH NO HISTORY 30 DAYS.