BMW DTC P20C4 – Reductant Heater ‘C’ Control Circuit High
DTC P20C4 meaning on BMW
The Diagnostic Trouble Code (DTC) P20C4 for BMW refers to the Reductant Heater ‘C’ Control Circuit High. This code indicates that there is a high voltage condition detected in the control circuit of the Reductant Heater ‘C’, which is part of the vehicle’s emissions control system.
BMW DTC P20C4 symptoms
Symptoms of the BMW DTC P20C4 may include:
- Check Engine Light illuminated
- Reduced engine performance
- Possible increase in emissions
BMW DTC P20C4 causes
Common causes of the BMW DTC P20C4 may include:
- Faulty Reductant Heater ‘C’
- Short circuit or open circuit in the control circuit
- Corrosion or poor connection in the wiring
BMW DTC P20C4 seriousness
The BMW DTC P20C4 is considered a moderate seriousness issue. While it may not cause immediate drivability concerns, it can lead to increased emissions and potential long-term engine performance issues if left unresolved.
How to diagnose DTC P20C4 on BMW
To diagnose the DTC P20C4 on a BMW, you can follow these steps:
- Use a diagnostic scanner to retrieve the fault codes
- Inspect the Reductant Heater ‘C’ and its control circuit for any visible damage
- Check the wiring and connectors for corrosion or poor connections
- Perform a continuity test on the control circuit to check for any open or short circuits
How to fix DTC P20C4 on BMW
To fix the DTC P20C4 on a BMW, you can try the following:
- Replace the faulty Reductant Heater ‘C’
- Repair any damaged wiring or connectors in the control circuit
- Clean any corrosion from the connections
- Clear the fault codes and perform a test drive to ensure the issue is resolved
How to erase DTC P20C4 on BMW
To erase the DTC P20C4 on a BMW, you can use a diagnostic scanner to clear the fault codes stored in the vehicle’s computer. Once the codes are cleared, you can perform a test drive to verify that the issue has been resolved.
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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