2023 Freightliner M2 106 - Cummins B6.7 - DEF Pump Not Priming

Question

Building a new fleet and one of our 2023 M2s is already down. 12,000 miles on the clock. It's throwing 'Low DEF Pressure' codes. When you turn the key on, you can hear the pump clicking, but it never seems to prime or build pressure.

I've pulled the line at the doser and no fluid is coming out. The tank is full of fresh Peak BlueDEF. I don't see any kinks in the lines from the tank to the pump. Is it possible the pump failed this early?

EmissionsEric · Answer

✅ Confirmed fix: Found a small air leak on the suction side connector at the DEF tank. The O-ring was rolled from the factory. The pump was sucking air instead of fluid, preventing it from ever reaching prime pressure. Replaced the quick-connect fitting and the system primed immediately.

GarageGuyDave · Answer

Check for a blockage in the DEF tank pickup screen. Sometimes plastic shavings from the manufacturing of the tank get sucked into the inlet and block flow.

2023 Freightliner M2 106 - Cummins B6.7 - DEF Pump Not Priming

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