B737-800
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 150; Flight Crew Type 1500
Human-Machine Interface
Aircraft Equipment Problem Less Severe
Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Flight Cancelled / Delayed
Aircraft
During the takeoff roll at approximately 75 knots; the Master Caution light illuminated. No indication was made on the annunciator panel and it was unclear what caused the Master Caution light to illuminate. The Captain elected to abort the takeoff. After clearing the runway we saw that the number 2 Engine Control annunciator was illuminated. 'Overhead' was never illuminated on the annunciator panel. We taxied back to a gate; called maintenance and swapped aircraft.
B737 First Officer reported Captain aborted takeoff due to Master Caution light illumination.