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DTC codes / P2Dxx · Hybrid propulsion / P2D20

P2D20Reductant System Flow – Blocked

P2D20 indicates that the engine control module has detected a blocked flow condition within the diesel exhaust fluid (DEF) reductant system, meaning the fluid cannot move as expected through the lines, injector, or metering components. The computer typically compares commanded reductant delivery with feedback from pressure or flow sensors and sets this code when the measured flow falls below the expected threshold for a calibrated time.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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