Date: 201409
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Dash 8 Series Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower ZZZ
Aircraft component: Oil Pressure Indication
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Time Pressure; Confusion; Distraction; Situational Awareness
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Maintenance Action
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Aircraft

Narrative: My flight crew and I performed a rejected takeoff from runway 34 due to a master warning light illuminating. Takeoff roll began relatively normal although I faintly thought I saw the master warning light blink as I finished my before takeoff flow while lining up on the runway. I kept this in mind but did not notify the PIC as I was unsure if I actually saw anything and indications were all normal for this phase of flight. However shortly before calling out V1 about 85-90 knots the master warning press to reset light illuminated continuously along with the #1 engine low oil pressure warning light. Immediately without hesitation I called for the captain to reject the takeoff and quickly informed the tower and noted the airspeed as the captain performed the rejected takeoff maneuver. We quickly cleared the runway onto the taxiway with the tower's approval and set the parking brake and together assessed the situation. The warning lights quickly extinguished after performing the rejected takeoff and we noted all systems were indicating normally. We informed the passengers and operations and returned to the gate. At this time we deplaned the passengers and contacted maintenance to make the appropriate write up in the logbook. I determined that a rejected takeoff was necessary upon illumination of the master warning light and being aware that we still had not achieved V1. The warning light was the sole determining factor in my decision to call for a rejected takeoff.I believe maintenance found the engine to be a couple quarts low on oil and also clean the cannon plugs and that this is what contributed to the event occurring. As far as rejecting the takeoff my flight crew and I decided to reject for safety reasons and to comply with standard operating procedures. I then informed the tower we were rejecting the takeoff and asked if we could clear the runway at taxiway E or F which the tower approved. I also noted the speed at which we rejected shortly after I called for the rejected takeoff. We then set the parking brake; discussed the situation and verified all systems were indicating normally at that time and informed the passengers of the situation before proceeding to the gate. However it is of my opinion that this situation may have been caused by a false warning indication as the oil pressure appeared to be within normal limits throughout the entirety of the event.


Second narrative: [Report narrative contained no additional information.]


Synopsis: A DHC-8-100 First Officer called for a reject after he saw the Master Warning and OIL PRESSURE lights illuminated during the takeoff roll. After clearing the runway all indications were again normal but at the gate oil was added and a cannon plug cleaned.