P0678 2016 Chevrolet Silverado Code - Cylinder 8 Glow Plug Circuit Fault
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. 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 2016 Chevrolet Silverado 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 2016 Chevrolet Silverado Description
Control of the glow plugs is accomplished by the Glow Plug Control Module. The nominal voltage for the glow plugs is 5.4 volts. When the ignition is turned On, the Glow Plug Control Module applies 7.2 V for 2.2 s, then 5.7 V for 0.8 s, and then 5.4 V until 1200°C (2192°F) is reached. The maximum voltage of the system is 10 V. While the engine is running the voltage will vary between 4.7 - 10 V when in closed loop control to maintain a glow plug temperature that ranges from 1150° - 1180°C (2102° - 2156°F). The temperature and the power consumption are controlled between the Engine Control Module (ECM) and the Glow Plug Control Module within a wide range to suit the engine's pre-heating requirements. Each glow plug is energized individually. This capability yields more optimum heat times for the glow plugs, thus pre - glow times can be kept to a minimum for a short wait to crank times and maximum glow plug durability.
What are the Possible Causes of the DTC P0678 2016 Chevrolet Silverado?
- 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 Control Module (GPCM)
How to Fix the DTC P0678 2016 Chevrolet Silverado?
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 2016 Chevrolet Silverado 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.
Need more information about the P0678 2016 Chevrolet Silverado code?
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Frequently Asked Questions about P0678 2016 Chevrolet Silverado Code
What does OBDII code P0678 mean on a 2016 Chevrolet Silverado?
Code P0678 indicates a fault in the glow plug circuit for cylinder 8, which may affect the engine's ability to start in cold conditions.
What are the symptoms of code P0678 on a Silverado?
Common symptoms include difficulty starting the engine in cold weather, reduced fuel efficiency, and possible illumination of the check engine light.
What causes the P0678 code to appear?
Causes can include a failed glow plug for cylinder 8, damaged wiring or connectors in the glow plug circuit, or issues with the glow plug control module.
Can I drive my Silverado with the P0678 code?
While the truck may still be drivable, cold starts may be difficult, and ignoring the issue could lead to further damage over time.
How do you diagnose code P0678?
Diagnosis typically involves inspecting the glow plug for cylinder 8, checking the wiring and connectors for damage, and testing the glow plug control module using a multimeter.
How do you fix a P0678 code on a 2016 Chevrolet Silverado?
Repairs may include replacing the faulty glow plug, repairing damaged wiring or connectors, or replacing the glow plug control module if it is defective.
How much does it cost to fix code P0678?
The cost depends on the exact issue but typically ranges from $100 to $300 for parts and labor, depending on whether the glow plug or control module needs replacement.
Can I replace the cylinder 8 glow plug myself?
Yes, replacing a glow plug is generally straightforward with basic tools, but ensure you have the correct replacement part and consult the vehicle manual for instructions.
What happens if I ignore the P0678 code?
Ignoring the code can lead to worsening cold start issues, reduced engine efficiency, and potential damage to other components in the glow plug circuit.
Is code P0678 common in diesel engines?
Yes, glow plug circuit faults are relatively common in diesel engines, especially in colder climates where glow plugs are essential for starting.
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