On June 1, 2015, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE15-021 to investigate 9 complaints alleging incidents of unintended braking in model year (MY) 2014 Jeep Grand Cherokee vehicles, including 2 alleging incidents of full ABS braking.ODI expanded the scope to include MY 2015 Grand Cherokee vehicles and identified a total of 176 incidents in complaints provided by FCA or submitted to ODI by consumers.ODI conducted the following work to assess the alleged defect in the subject vehicles:1) evaluated the design of the subject Forward Collision Warning (FCW) system, including the maximum braking authority during automated braking; 2) analyzed the frequency and severity of field incidents of unintended braking; 3) analyzed warranty data for evidence of system faults that may be related to the alleged defect; and 4) reviewed the performance of the subject system in testing conducted as part of NHTSA?s 2014 Automatic Emergency Braking (AEB) test program.ODI?s analysis found that the maximum brake activations that can be commanded by the subject system are limited in both braking force and duration.The system is not capable of achieving full ABS braking, as alleged in some complaints, unless driver brake application triggers the Advanced Brake Assist (ABA) mode.Analysis of field data found that unintended braking events occur randomly for a variety of causes and are not driven by any single environmental factor, traffic condition, or vehicle fault.The incidents involve short duration moderate braking events with minimal changes in vehicle speed.None of the incidents resulted in crash or injuries.The subject vehicles performed as well or better than peer vehicles in testing conducted as part of NHTSA?s AEB test program.This preliminary evaluation is closed. The closing of this investigation does not constitute a finding that a safety related defect does not exist. For additional information, see the closing resume appendix and the investi