DIAGNOSIS This is overheating protection kicking in. The tool is getting too hot, either from extreme workload, a dirty motor, or a failing component causing excess resistance.
FIX Let the tool cool down completely. Check your application—are you driving massive lag bolts non-stop? You're overloading it. Use a more powerful tool like an impact wrench for that. Ensure the air vents near the motor aren't clogged with dust.
IF THAT DIDN'T WORK The thermal sensor or motor might be faulty, causing premature shutdown. Try a different, fully charged battery to rule out a weak battery causing high current draw and heat.
HEADS UP If it happens with light-duty tasks and a cool tool, it's an electronic fault. The tool needs professional diagnosis; the control board is likely involved.