P0678 2016 GMC Sierra Code - Cylinder 8 Glow Plug Circuit Fault
Quick Answer
The P0678 diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a fault in the glow plug circuit of cylinder 8. Common causes include Faulty glow plug in cylinder 8, Damaged wiring or connectors in the glow plug circuit, Defective glow plug control module. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0678 2016 GMC Sierra indicates Cylinder 8 Glow Plug Circuit Fault.
- Common causes
- Common causes include Faulty glow plug in cylinder 8, Damaged wiring or connectors in the glow plug circuit, Defective glow plug control module.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0678 2016 GMC Sierra Description
The P0678 diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a fault in the glow plug circuit of cylinder 8. Glow plugs are essential components in diesel engines as they heat the combustion chamber during cold starts, aiding in the ignition process. Cylinder 8 is one of the cylinders in the engine, and a fault in its glow plug circuit can lead to difficulties starting the vehicle, reduced engine performance, and potential long-term damage if not addressed promptly.
Common Causes of P0678 2016 GMC Sierra
- Faulty glow plug in cylinder 8.
- Damaged wiring or connectors in the glow plug circuit.
- Defective glow plug control module.
- Blown fuse related to the glow plug circuit.
- ECM malfunction affecting the glow plug circuit.
Symptoms of P0678 2016 GMC Sierra
- Difficulties starting the vehicle, especially in cold weather.
- Rough idling or engine misfires.
- Reduced engine performance and power.
- Increased fuel consumption.
- Illumination of the check engine light on the dashboard.
How to Fix P0678 2016 GMC Sierra
- Perform a thorough diagnostic scan to retrieve the P0678 code and confirm the issue.
- Inspect the glow plug in cylinder 8 for proper operation and replace if necessary.
- Check the wiring and connectors in the glow plug circuit for any damage or corrosion, repairing or replacing as needed.
- Test the glow plug control module and replace if found to be faulty.
- Clear the DTC and perform a test drive to ensure the issue has been resolved.
Cost to Fix P0678 2016 GMC Sierra
The typical repair costs for a cylinder 8 glow plug circuit fault can vary depending on the specific cause of the issue and the necessary repairs. In general, replacing a glow plug can cost between $50 to $200 per plug, while repairing damaged wiring or connectors may range from $100 to $300. If the glow plug control module needs replacement, it can cost anywhere from $200 to $500. Labor costs can add an additional $100 to $300, with total repair costs potentially ranging from $300 to $1000 or more. It's recommended to consult with a trusted mechanic or auto repair shop for a more accurate estimate based on the specific circumstances of the vehicle and the location.
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