BMW DTC P0679 – Cylinder 9 Glow Plug Circuit/Open
DTC P0679 meaning on BMW
DTC P0679 indicates a fault in the glow plug circuit for cylinder 9 in a BMW vehicle. The Engine Control Module (ECM) monitors the resistance of the glow plug circuit, and if it detects an open circuit or high resistance in the circuit for cylinder 9, it triggers this diagnostic trouble code.
BMW DTC P0679 symptoms
Symptoms of DTC P0679 in a BMW may include:
- Hard starting or extended cranking time
- Rough idling or misfiring
- Reduced engine performance
- Check Engine Light (CEL) illuminated on the dashboard
BMW DTC P0679 causes
The common causes of DTC P0679 in a BMW are:
- Defective glow plug in cylinder 9
- Wiring issues in the glow plug circuit
- Faulty glow plug relay
- Corrosion or poor connections in the circuit
BMW DTC P0679 seriousness
Ignoring DTC P0679 in a BMW can lead to starting difficulties, rough running, and potential engine damage due to incomplete combustion. It is important to address this issue promptly to ensure proper engine operation and prevent further complications.
How to diagnose DTC P0679 on BMW
To diagnose DTC P0679 on a BMW, you can follow these steps:
- Use a diagnostic scanner to retrieve the fault codes from the ECM.
- Inspect the glow plug in cylinder 9 for proper operation and resistance.
- Check the wiring and connections in the glow plug circuit for any damage or corrosion.
- Test the glow plug relay for functionality.
How to fix DTC P0679 on BMW
To fix DTC P0679 on a BMW, you can take the following actions:
- Replace the faulty glow plug in cylinder 9.
- Repair any damaged wiring or connections in the glow plug circuit.
- Replace the glow plug relay if it is found to be defective.
- Clear the fault codes using a diagnostic scanner after the repairs are completed.
How to erase DTC P0679 on BMW
To erase DTC P0679 on a BMW, you can use a diagnostic scanner to clear the fault codes stored in the ECM’s memory. After addressing the underlying issue causing the fault code and making the necessary repairs, you can reset the codes to turn off the Check Engine Light and ensure the system is functioning properly.
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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