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TuningBot DTC Database · v4.37.14

P221C Reductant Heater B Current Too Low

Generic (OBD-II) interpretation in the TuningBot DTC database.

P · PowertrainEmissionsOBD2

What P221C means

P221C
Reductant Heater B Current Too Low Generic · emissions Data confidence 65%

The control module detected that the Reductant Heater B Current value was below the expected limit.

Symptoms

  • MIL or SCR/AdBlue warning illuminated
  • Possible start-count-down or torque limitation on some applications

Possible causes

  • Reductant quality or level fault
  • Dosing valve or supply module fault
  • NOx sensor fault
  • Frozen or crystallized reductant lines
  • Wiring or connector fault

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

Related and nearby codes

P22 range
P2200P2201P2202P2203P2204P2205P2206P2207P2208P2209P220AP220BP220CP220DP220EP220FP2210P2211

How to read P221C

P

Powertrain: engine, transmission and driveline systems.

2

Generic SAE-standard code: same meaning on every make.

21C

Specific fault index within the subsystem.

Frequently asked questions about P221C

What does P221C mean?

Reductant Heater B Current Too Low. The control module detected that the Reductant Heater B Current value was below the expected limit.

Is P221C generic or manufacturer-specific?

P221C is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove P221C at file level?

If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry and, where the ECU needs it, corrects the checksum too. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.

Other file services

Stage 1/2/3 TuningDPF RemovalEGR RemovalAdBlue / SCR RemovalDTC RemovalIMMO OFFSpeed Limiter (Vmax)

Understand the system behind this code: SCR / AdBlue System

ECU tuningDyno-tested results by model and engine See the results →

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