DDE A0001409678 | Genuine Freightliner® DEF Pump, Exchange Supply Unit

1. Delivers DEF to clean exhaust gases

• The DEF pump moves Diesel Exhaust Fluid from the DEF tank to the exhaust system.

• DEF is injected into the exhaust to break down harmful nitrogen oxides (NOx) into safer gases (nitrogen and water vapor).

2. Controls the correct amount and pressure

• The supply unit makes sure DEF is delivered at the right pressure and quantity.

• This prevents:

  • Too much DEF (which can damage components)

  • Too little DEF (which causes emission failures and warning lights)

3. Keeps the vehicle legal and operational

• Proper DEF delivery helps the vehicle meet emissions regulations.

• If the DEF pump fails, many vehicles will:

  • Show DEF or check engine warnings

  • Reduce engine power

  • Eventually limit or prevent engine starting

4. Why use an Exchange Supply Unit specifically

• It replaces a failed pump with a remanufactured, tested unit.

• It’s:

  • Faster to install than repairing parts

  • More affordable than buying new

  • Designed to restore full system function

Warning lights & messages

• DEF / SCR warning light comes on

• Check Engine Light

• Messages like:

  • “DEF system fault”

  • “Service DEF system”

  • “Emissions system problem”

  • “No engine restart in ___ miles”

Engine performance issues

• Reduced engine power (limp mode)

• Engine speed or vehicle speed may be limited

• In some cases, the vehicle won’t start after a countdown

DEF-related problems

• DEF level doesn’t change even after driving

• DEF consumption is abnormal (using too much or none at all)

• Crystallized DEF around the pump or lines (white powder)

• DEF leaks under the vehicle

Noises or pump behavior

• No priming sound from the DEF pump when the key is turned on

• Clicking, buzzing, or whining noises from the DEF pump area

Diagnostic trouble codes (examples)

• Codes related to DEF pressure, flow, or pump control

• SCR efficiency or NOx sensor faults caused by poor DEF delivery

Cold-weather symptoms

• DEF system fails to build pressure after startup

• Longer warm-up times before warnings clear