P0677 2016 GMC Sierra Code - Cylinder 7 Glow Plug Circuit Fault
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #7 glow plug, Cylinder #7 glow plug harness is open or shorted, Cylinder #7 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
- P0677 2016 GMC Sierra indicates Cylinder 7 Glow Plug Circuit Fault.
- Common causes
- Common causes include Faulty cylinder #7 glow plug, Cylinder #7 glow plug harness is open or shorted, Cylinder #7 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 P0677 2016 GMC Sierra 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 P0677 2016 GMC Sierra?
- Faulty cylinder #7 glow plug
- Cylinder #7 glow plug harness is open or shorted
- Cylinder #7 glow plug circuit poor electrical connection
- Faulty Glow Plug Control Module (GPCM)
How to Fix the DTC P0677 2016 GMC Sierra?
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 P0677 2016 GMC Sierra 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 P0677 2016 GMC Sierra code?
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Frequently Asked Questions about P0677 2016 GMC Sierra Code
What does the OBDII code P0677 mean for a 2016 GMC Sierra?
Code P0677 indicates a fault in the glow plug circuit for cylinder 7, typically due to an electrical issue with the glow plug or its wiring.
What are the symptoms of P0677 in a 2016 GMC Sierra?
Common symptoms include difficulty starting the engine in cold weather, rough idling, reduced engine performance, and the check engine light turning on.
What causes the P0677 code in a 2016 GMC Sierra?
Common causes include a failed cylinder 7 glow plug, damaged wiring or connectors, a faulty glow plug control module, or corrosion in the glow plug circuit.
Can I drive my 2016 GMC Sierra with the P0677 code?
While the truck may still run, driving with this code can lead to starting issues in cold weather and may affect engine performance over time. It’s best to address the issue promptly.
How do I diagnose the P0677 code on my 2016 GMC Sierra?
Start by inspecting the glow plug for cylinder 7, checking for signs of damage or wear. Test the glow plug circuit with a multimeter and look for wiring or connector issues.
How do I fix the P0677 code on a 2016 GMC Sierra?
Repairs typically involve replacing the faulty cylinder 7 glow plug, repairing damaged wiring or connectors, or replacing the glow plug control module if necessary.
How much does it cost to repair the P0677 code on a 2016 GMC Sierra?
Costs vary, but replacing a glow plug typically ranges from $50 to $150, while wiring repairs or module replacements can cost more depending on labor and parts.
What tools are needed to repair the P0677 code on a 2016 GMC Sierra?
Common tools include a socket wrench, multimeter, and possibly a wiring repair kit or glow plug removal tool.
Can a bad glow plug cause long-term engine problems?
Yes, unresolved glow plug issues can lead to starting difficulties, reduced fuel efficiency, and increased emissions over time.
How can I prevent the P0677 code from recurring?
Regularly inspect the glow plugs, wiring, and connectors for wear or corrosion, especially before cold weather. Maintaining the glow plug system can help prevent recurring issues.
Discuss the causes and fixes for P0677 2016 GMC Sierra OBDII Code
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