BMW DTC P1391 – Ionic Current Voltage Selection Measuring-Circuit High
DTC P1391 meaning on BMW
The Diagnostic Trouble Code (DTC) P1391 for BMW refers to the Ionic Current Voltage Selection Measuring-Circuit High. This code indicates that there is a high voltage reading in the circuit responsible for measuring the ionic current in the engine.
BMW DTC P1391 symptoms
Symptoms associated with BMW DTC P1391 may include:
- Check Engine Light (MIL) illuminated on the dashboard
- Engine running rough or misfiring
- Reduced engine performance
- Potential stalling or difficulty starting the engine
BMW DTC P1391 causes
Common causes of BMW DTC P1391 include:
- Faulty ionic current module
- Wiring or connection issues in the ionic current circuit
- Corrosion or poor contact in the circuit components
- ECU (Engine Control Unit) malfunction
BMW DTC P1391 seriousness
Ignoring or neglecting BMW DTC P1391 can lead to potential engine performance issues and may cause further damage to engine components. It is recommended to address this code promptly to prevent any long-term problems.
How to diagnose DTC P1391 on BMW
To diagnose BMW DTC P1391, a mechanic would typically perform the following steps:
- Use a diagnostic scanner to retrieve the fault codes and confirm the presence of P1391.
- Inspect the ionic current circuit for any visible damage, corrosion, or loose connections.
- Test the ionic current module and related components for proper functionality.
- Check the ECU for any potential malfunctions that could be causing the high voltage reading.
How to fix DTC P1391 on BMW
To fix BMW DTC P1391, the following steps may be taken:
- Repair or replace any damaged wiring or connections in the ionic current circuit.
- Replace the faulty ionic current module if necessary.
- Clean any corrosion or debris from the circuit components.
- If the ECU is determined to be the issue, it may need to be reprogrammed or replaced.
How to erase DTC P1391 on BMW
After addressing the underlying issue causing BMW DTC P1391, the code can be erased using a diagnostic scanner. The scanner can clear the fault codes stored in the ECU, and once the repairs are completed, the code should not reappear if the problem has been resolved successfully.
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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