Hi Raghvendran,
The other possible option is that you may create a returns sales order with a returns item category in ECC directly & then create a purchase requisition from the returns orders.
Create a PR to PO & then create an outbound delivery to goods issue the vehicle back to OEM.
No sure whether you can assign the VIN number to the PO / PR.
This is how I can see the best possible way through the standard SAP.
Else there are many custom options available to tackle the same requirement
Regards,
Sachin Balmiki