Boeing has found a new software problem on its grounded 737 Max jetliner

The aircraft maker says it is making the necessary changes and working with the Federal Aviation Administration. It's up to the FAA to decide when the plane is safe and can resume flying. 

The latest problem has to do with monitors that verify key systems on the plane are working. According to a person familiar with the situation, during a recent test, one of the monitors didn't start up when it was supposed to. 

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The Max has been grounded since two crashes killed 346 people.