The hybrid models have a coolant pump that cools control electronics. The pump can fail or spin slowly, which causes a Check Engine Light to illuminate and complete engine shut down.
Resources for the Repair and Maintenance of your 2010 Mercury Mariner Hybrid
2010 Mercury Mariner Hybrid
2010 Mercury Mariner Hybrid Problems
Hard driving conditions, including quick starts from a stop and hard acceleration up hills, can cause the rear motor mount to crack. The broken motor mount needs to be replaced, otherwise damage to the hybrid drive system may result.
2010 Mercury Mariner Hybrid Reviews
Monday, went to open the car, and neither remote would work. The touch pad on the door also would not work. Opened the door with the key, and the motor would start, but could not get out of park. None of the digital/electronic displays worked. Windows nor locks would work. Air conditioner and cruise did. I was able to drive the car by disabling the "Park/Transmission" lock switch. The dealer doesn't seem to have an idea as to what is wrong.