BMW DTC P20C0 – Reductant Heater ‘B’ Control Circuit High
DTC P20C0 meaning on BMW
DTC P20C0 for BMW refers to the Reductant Heater ‘B’ Control Circuit High. This diagnostic trouble code indicates that there is a high voltage condition detected in the control circuit of the Reductant Heater ‘B’. The reductant heater is a component of the Selective Catalytic Reduction (SCR) system, which helps reduce emissions by converting nitrogen oxides into harmless nitrogen and water vapor.
BMW DTC P20C0 symptoms
Symptoms of DTC P20C0 on a BMW may include the malfunction indicator lamp (MIL) or check engine light illuminating on the dashboard. Additionally, you may experience reduced engine performance or poor fuel efficiency. In some cases, the vehicle may go into a reduced power mode to prevent further damage.
BMW DTC P20C0 causes
The high voltage condition in the Reductant Heater ‘B’ Control Circuit can be caused by various factors. Common causes include a faulty reductant heater, damaged wiring or connectors in the control circuit, or a malfunctioning powertrain control module (PCM).
BMW DTC P20C0 seriousness
While DTC P20C0 may not cause immediate drivability issues, it is important to address this fault promptly to prevent further damage to the emissions control system. Ignoring this fault can lead to increased emissions and potential regulatory compliance issues.
How to diagnose DTC P20C0 on BMW
To diagnose DTC P20C0 on a BMW, a diagnostic scan tool capable of reading fault codes and live data is required. The technician should start by checking the freeze frame data to understand the conditions under which the fault occurred. Next, a visual inspection of the reductant heater, wiring, and connectors should be performed to look for any visible damage or corrosion. Testing the resistance of the reductant heater and checking for proper voltage supply to the control circuit are essential steps in diagnosing this fault.
How to fix DTC P20C0 on BMW
Fixing DTC P20C0 on a BMW typically involves replacing the faulty reductant heater ‘B’ if it is determined to be the root cause of the high voltage condition. Additionally, repairing any damaged wiring or connectors in the control circuit is necessary. It is recommended to follow the manufacturer’s diagnostic and repair procedures outlined in the service manual to ensure a proper fix. Once the repairs are completed, the fault codes should be cleared, and the vehicle should be tested to verify that the issue has been resolved.
How to erase DTC P20C0 on BMW
To erase DTC P20C0 on a BMW, a diagnostic scan tool capable of clearing fault codes is required. The technician should access the vehicle’s onboard diagnostic system using the scan tool, navigate to the fault code menu, and select the option to clear the stored fault codes. Once the fault codes have been successfully cleared, it is recommended to perform a road test to ensure that the check engine light does not reappear, indicating that the fault has been properly addressed.
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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