Dorman Products Tech Tip: Priming a DEF pump

Dorman Products provides tips on priming prior to installing the Diesel Exhaust Fluid (DEF) Pump, No. 904-609, applicable to Ford 2019-11 model year vehicles.

When installing a new DEF pump on certain Ford vehicles, it is necessary to prime the pump prior to installation. The following tech note provides important tips on priming the No. 904-609 DEF pump using the included 30cc syringe.

Before you begin

• Always wear proper safety equipment when performing repairs.
• Ensure this part fits the exact vehicle year, make, model, and configuration. This can be verified at the point of purchase using the part number on the box or using the part number above at DormanProducts.com.
• Reference the appropriate service manual for the vehicle. If you do not have a service manual, and do not have the training or experience to perform the necessary procedures correctly, seek the services of a qualified technician.

In order to ensure proper operation once the replacement Diesel Exhaust Fluid (DEF) supply module assembly (pump) is installed on the DEF tank, it needs to be primed.

A container of clean DEF is necessary for this procedure. Please follow the instructions below to prime the pump.

Priming instructions

1. Remove the yellow protective cap from the hydraulic line connection of the pump (refer to Photo 1).
2. Hold the pump upside down on a clean flat surface. Make sure no dirt or other contaminants can enter the pump inlet port.
3. Remove the large yellow protection cap from the pump inlet port on the bottom of the pump. CAUTION: Do not remove the small yellow cap at this time (this is the backflow or return port).
4. Using the supplied 30cc syringe and a new, clean container of DEF, fill the syringe at least half full.
5. Insert the nozzle of the filled syringe into the inlet port on the bottom of the pump. Slowly push the plunger of the syringe to force the clean DEF into the pump until the syringe is empty (refer to Photo 1). Discard the syringe.
6. Remove the small yellow protective cap from the backflow port (refer to Photo 1).
7. Following the installation procedures outlined in the Workshop Manual, install the new pump onto the DEF tank. CAUTION: It is very important that the mounting area of the tank is as clean as possible. No dirt can be allowed to drop into the inlet tube of the DEF tank during this procedure.
8. If necessary, wipe off any DEF residue which may have dripped out of the pump during installation.

Disclaimer: Even though every attempt is made to ensure this information is complete and accurate, it is impossible to account for all possible circumstances or situations. Please consult with a qualified technician before attempting to perform any work you are not qualified to do. Automobiles can be hazardous to work on; be sure to take all necessary safety precautions. Failure to do so may result in property damage or personal injury. Certain motor vehicle standards and performance requirements may apply to your motor vehicle (such as Federal Motor Vehicle Safety Standards by the National Highway Traffic Safety Administration). Be sure that your work is performed in accordance with such standards and that you do not disable any motor vehicle safety feature.