P0678 2017 GMC Sierra Code - Cylinder 8 Glow Plug Circuit Fault
Quick Answer
The diagnostic trouble code P0678 for a 2017 GMC Sierra indicates a fault in the cylinder 8 glow plug circuit. 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 2017 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 2017 GMC Sierra Description
The diagnostic trouble code P0678 for a 2017 GMC Sierra indicates a fault in the cylinder 8 glow plug circuit. Glow plugs are crucial components in diesel engines, responsible for heating the combustion chamber during cold starts. The glow plug circuit ensures that the plugs receive the necessary voltage to reach the required temperature for efficient starting. When this circuit malfunctions, it can lead to various issues with the engine's performance.
Common Causes of P0678 2017 GMC Sierra
- Faulty glow plug in cylinder 8
- Damaged wiring or connectors in the glow plug circuit
- Defective glow plug control module
- Blown fuse in the glow plug circuit
- Corrosion or poor connections in the circuit
Symptoms of P0678 2017 GMC Sierra
- Hard starting, especially in cold weather
- Rough idling and poor acceleration
- Engine misfires or hesitation
- Excessive smoke from the exhaust
- Decreased fuel efficiency
How to Fix P0678 2017 GMC Sierra
- Diagnose the specific cause of the fault using a diagnostic tool
- Inspect the glow plug in cylinder 8 and replace if faulty
- Check wiring and connectors for damage, repair or replace as needed
- Test the glow plug control module and replace if defective
- Replace any blown fuses in the glow plug circuit
Cost to Fix P0678 2017 GMC Sierra
The cost of repairing a cylinder 8 glow plug circuit fault can vary depending on the specific cause and the labor rates at the auto repair shop. Generally, the cost of replacing a glow plug can range from $50 to $150 per plug, including parts and labor. If additional components such as the glow plug control module or wiring need to be replaced, the cost can increase. Overall, the total repair cost for this issue can range from $150 to $500 or more, depending on the extent of the repairs needed. It is advisable to consult with a qualified mechanic or auto repair shop for a more accurate cost estimate based on the specific diagnosis for your vehicle.
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