BMW DTC P221D – Reductant Heater ‘B’ Current Too High
DTC P221D meaning on BMW
DTC P221D on a BMW indicates that the reductant heater ‘B’ current is too high. The reductant heater is a component of the Selective Catalytic Reduction (SCR) system, which helps reduce harmful emissions by converting nitrogen oxides into nitrogen and water vapor.
BMW DTC P221D symptoms
Symptoms of DTC P221D on a BMW may include the Check Engine Light illuminating on the dashboard, reduced engine performance, increased fuel consumption, and potential emissions issues during vehicle inspections.
BMW DTC P221D causes
The high current in the reductant heater ‘B’ circuit that triggers DTC P221D on a BMW can be caused by a faulty reductant heater, damaged wiring or connectors in the heater circuit, or a malfunctioning SCR system.
BMW DTC P221D seriousness
While DTC P221D may not cause immediate drivability issues, it is important to address this fault promptly to ensure proper emissions control and prevent potential long-term damage to the SCR system.
How to diagnose DTC P221D on BMW
To diagnose DTC P221D on a BMW, a mechanic would typically use a diagnostic scanner to retrieve the fault code and then perform a visual inspection of the reductant heater ‘B’ circuit, checking for any visible damage or loose connections. Further testing may involve checking the resistance of the heater element and verifying proper voltage supply to the heater.
How to fix DTC P221D on BMW
Fixing DTC P221D on a BMW may involve replacing the faulty reductant heater ‘B’, repairing any damaged wiring or connectors in the circuit, or addressing any underlying issues with the SCR system. It is recommended to follow the manufacturer’s diagnostic and repair procedures to ensure a proper fix.
How to erase DTC P221D on BMW
Once the underlying issue causing DTC P221D on a BMW has been resolved, the fault code can be cleared using a diagnostic scanner. This will reset the Check Engine Light and erase the DTC from the vehicle’s memory. It is important to verify that the repair was successful by performing a test drive and re-scanning the vehicle for any remaining fault codes.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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