P20B5Reductant metering unit heater control - open
Generic (OBD-II) interpretation in the TuningBot DTC database.
P · PowertrainEmissionsOBD2
What P20B5 means
P20B5
Reductant metering unit heater control - open
Generic · emissions
Data confidence78%
The control module detected a fault associated with the Reductant metering unit heater control - open circuit or function; the stored code identifies the affected component rather than a single failure mode.
Symptoms
MIL or SCR/AdBlue warning illuminated
Possible start-count-down or torque limitation on some applications
Possible causes
Circuit wiring
reductant heater
ECM
Recommended checks
Read NOx sensor values and dosing system status
Check reductant level and quality data
Inspect dosing valve, lines and heater operation
Check wiring and connectors of the SCR components
Check for OEM technical bulletins and software updates
Powertrain: engine, transmission and driveline systems.
2
Generic SAE-standard code: same meaning on every make.
0B5
Specific fault index within the subsystem.
Frequently asked questions about P20B5
What does P20B5 mean?
Reductant metering unit heater control - open. The control module detected a fault associated with the Reductant metering unit heater control - open circuit or function; the stored code identifies the affected component rather than a single failure mode.
Is P20B5 generic or manufacturer-specific?
P20B5 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P20B5 at file level?
If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.
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