P0677 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 2018 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 P0677 2018 Chevrolet Silverado?
- 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 2018 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 P0677 2018 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 P0677 2018 Chevrolet Silverado code?
Need more information on how to fix the P0677 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0677 2018 Chevrolet Silverado code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0677 2018 Chevrolet Silverado Code
1. What does the OBDII code P0677 mean on a 2018 Chevrolet Silverado?
P0677 indicates a fault in the glow plug circuit for cylinder 7, meaning the system detected an issue with the electrical circuit or the glow plug itself.
2. What are the symptoms of a P0677 code?
Symptoms may include difficulty starting the engine in cold weather, rough idling, reduced fuel efficiency, and an illuminated check engine light.
3. What causes the P0677 code to appear?
Common causes include a faulty glow plug in cylinder 7, damaged wiring or connectors in the glow plug circuit, a bad glow plug control module, or corrosion in the electrical connections.
4. How do I diagnose a P0677 code?
Diagnosis involves checking the glow plug for cylinder 7, inspecting the wiring and connectors for damage or corrosion, testing the glow plug circuit with a multimeter, and scanning for any related codes.
5. Can I drive my 2018 Silverado with a P0677 code?
While the truck may still run, driving with this code can cause starting issues in cold weather, reduced performance, and inefficiency. It's best to address the issue promptly.
6. How do I fix a P0677 code?
Repairs may include replacing the cylinder 7 glow plug, repairing or replacing damaged wiring or connectors, or replacing the glow plug control module if it's malfunctioning.
7. How much does it cost to repair a P0677 code?
Replacing a single glow plug typically costs between $100 and $300, depending on labor rates and parts costs. Wiring or module repairs may cost more.
8. Can a bad glow plug damage my engine?
A single bad glow plug usually won’t damage your engine, but failing to address the issue can lead to hard starts, misfires, and increased wear on other components over time.
9. How can I prevent a P0677 code from recurring?
Regular maintenance, including inspecting glow plugs and wiring for damage or corrosion, can help prevent this code from reappearing.
10. Do I need to replace all glow plugs if one fails?
It's not mandatory, but replacing all glow plugs at the same time is often recommended, as they tend to wear out at similar rates.
Discuss the causes and fixes for P0677 2018 Chevrolet Silverado OBDII Code
Code P0677 2018 Chevrolet Silverado comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
