Code result
P221D
Reductant Heater B Current Too High
High severity
What it means
Reductant Heater B Current Too High: the control module has detected this fault condition. The reductant (DEF/AdBlue) heater keeps the urea fluid from freezing; a fault can impair SCR dosing in cold conditions.
Is it safe to drive?
No — stop driving
This code points to a problem that can cause damage or affect safety. Avoid driving and have the vehicle diagnosed promptly.
Most likely causes
Element partially shorted
highOne of the most commonly reported causes for this code — check this first.
Related help
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