P203E: Ram DEF-level errors during uneven thawing

Why liquid at the bottom can mislead

The documented P203E case concerns an intermittent or erratic DEF-level signal during freezing conditions. FCA explains that rapid temperature changes can thaw fluid at the tank’s lower surface while fluid nearer the center remains partly frozen. The diagnostic can become enabled before the whole tank has thawed. That makes temperature history relevant even when some DEF is visibly liquid.

Crystals and filling history matter too

The bulletin also identifies repeated freeze/thaw cycles that form crystals on the level-sensing focus tube, and it notes overfilling as a relevant condition. These observations help distinguish a level-measurement complaint from simply assuming the tank is empty or that every intermittent code represents a broken wire. Record the recent temperatures, fill history and other faults before choosing the bulletin’s repair path.

The documented correction has three parts

For the qualifying case, the repair combines a urea-delivery-module kit, the grade vent valve and dosing-control-unit software. Replacing only the sensor-related assembly without checking the vent and software does not reproduce the stated correction. The source also requires the final DEF quantity to be at least the level present when the vehicle arrived. Verify the exact engine and model applicability, then assess the original level indication and fault behavior after repair. This bulletin does not provide an owner procedure for heating the tank, adding substances to DEF or bypassing emissions functions. A remaining fault requires the appropriate current diagnostic procedure.

Source and applicability

FCA 25-007-24 concerns 2019–2022 Ram 2500/3500 pickups and 3500/4500/5500 cab-chassis trucks with the listed 6.7 L Cummins ETL, ETN or ETM engines.

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