Code result
P21DD
Reductant Heater A Current Too Low
Moderate severity
What it means
DEF heater A current draw is below threshold — partially-open winding.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Element partially open
highOne of the most commonly reported causes for this code — check this first.
Related help
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