The contact owns a 2020 Jeep Cherokee. The contact stated while driving at an undisclosed speed, there was a grinding sound coming from the vehicle and the service 4-WD warning light was illuminated. The contact parked the vehicle. The contact stated that the vehicle was undrivable. The vehicle was towed to an independent mechanic where it was diagnosed with PTU failure. The contact was informed that the PTU needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The contact referenced an unknown recall repair; however, the contact was informed that the VIN was not included in the recall. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 48,000.