Powertrain
Definition only
Lights the check engine lamp
P20BD: Reductant Heater B Control Circuit/Open
Standardized SAE J2012 code · P20xx — Fuel & air metering and auxiliary emission controls
What does P20BD mean?
Reductant heater B (next supply-line segment) control circuit open — that line segment will not be kept above freezing.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Common causes
- High Heater winding open
- Low Pin pushed back out of connector body
- Low Cracked solder joint inside the module or sensor
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P20BD on the same make and model first.
P20BD in the community
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