As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FLIGHT CREW REPORTED THAT THE NR 1 HYD ISO VALVE AND ROLL SPOILER INBD HYD CAUTION LIGHTS WERE ILLUMINATING INTERMITTENTLY ON THE GROUND. MAINTENANCE TROUBLESHOOTING DETERMINED THAT THE RESERVOIR LEVEL INDICATOR WAS STUCK AT 6 QTS AND THE FLUID LEVEL WAS NEAR EMPTY CAUSING THE INDICATIONS. THE HYD SYSTEM RESERVOIR WAS REPLACED AND THE ACFT WAS RETURNED TO SERVICE.