If you cant find DPF part number…
1. Use the vin number, customer provided you on check in sheet to call the dealer.
I normally always call dealer or multiple dealers to and say ” id like to get part number and pricing on the DPF, we have a customer coming that may or may not need a new DPF, but he can not have his truck down so i have to have it here in case he does need it” here is the vin number and here is a part number i show.. 529699723? sometimes you have to make up a part number so it sounds legit. (you gotta play that game sometimes) normally they will give you part number.
or you can google year make and model to get an idea of what DPF it has
or the DPF part number may have to be provided to you by the customer