OBD
P2D20
Reductant System Flow – Blocked
What it means
P2D20 means Reductant System Flow – Blocked.
Check these first
- Crystallized reductant blocking the injector
- Frozen or gelled reductant in the line
- A clogged reductant filter
- A failed reductant pump
- A kinked reductant line
What to do next
- Check the reductant filter
- Inspect the injector for crystallization
- Verify reductant pump pressure
- Scan for frozen or gelled reductant
- Replace the blocked component
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.