P0678 Ford Code - Cylinder 8 Glow Plug Circuit Fault
Quick Answer
The glow plug system is used to assist in providing the heat required to begin combustion during cold engine temperatures. Common causes include Faulty cylinder #8 glow plug, Cylinder #8 glow plug harness is open or shorted, Cylinder #8 glow plug circuit poor electrical connection. 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 Ford indicates Cylinder 8 Glow Plug Circuit Fault.
- Common causes
- Common causes include Faulty cylinder #8 glow plug, Cylinder #8 glow plug harness is open or shorted, Cylinder #8 glow plug circuit poor electrical connection.
- 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.
Code P0678 Ford Description
What are the Possible Causes of the DTC P0678 Ford?
- Faulty cylinder #8 glow plug
- Cylinder #8 glow plug harness is open or shorted
- Cylinder #8 glow plug circuit poor electrical connection
- Faulty glow plug module
How to Fix the DTC P0678 Ford?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0678 Ford code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0678 Ford Code
1. What does the OBDII code P0678 mean on a Ford vehicle?
P0678 indicates a fault in the cylinder 8 glow plug circuit, meaning the glow plug isn't functioning properly or there's an issue with its electrical system.
2. What are the symptoms of code P0678 on a Ford?
Symptoms may include difficulty starting the engine in cold weather, rough idling, decreased fuel efficiency, and an illuminated check engine light.
3. What causes the P0678 code on a Ford?
Common causes include a faulty glow plug, damaged glow plug wiring or connectors, a malfunctioning glow plug control module, or corrosion in the circuit.
4. Can I drive with the P0678 code on my Ford?
While you can drive with this code, it's not recommended, especially in cold weather, as starting issues and potential engine damage may occur.
5. How do you diagnose the P0678 code on a Ford?
Diagnosis typically involves using a multimeter to test the glow plug’s resistance, inspecting the wiring and connectors, and checking the glow plug control module for faults.
6. How do you fix the P0678 code on a Ford?
Repairs may include replacing the cylinder 8 glow plug, repairing damaged wiring or connectors, cleaning corrosion, or replacing the glow plug control module.
7. How much does it cost to fix the P0678 code on a Ford?
Costs can range from $50 to $200 for a glow plug replacement, while wiring or module repairs may cost more depending on labor and parts.
8. What tools are needed to fix the P0678 code on a Ford?
You’ll typically need a multimeter, basic hand tools, and possibly an OBDII scanner to diagnose and clear the code.
9. Can a bad glow plug cause engine damage in a Ford vehicle?
While rare, prolonged issues with glow plugs may lead to hard starts and increased wear on the engine, especially in cold climates.
10. How can you prevent the P0678 code from occurring on a Ford?
Regular maintenance, including inspecting glow plugs and wiring for damage or corrosion, can help prevent this code from appearing.
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