P0677 Chevrolet 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 Chevrolet 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 Chevrolet 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 Chevrolet?
- 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 Chevrolet?
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 Chevrolet 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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Information for Specific Chevrolet Models
- P0677 2014 Chevrolet Silverado — Cylinder 7 Glow Plug Circuit Fault
- P0677 2015 Chevrolet Silverado — Cylinder 7 Glow Plug Circuit Fault
- P0677 2016 Chevrolet Silverado — Cylinder 7 Glow Plug Circuit Fault
- P0677 2017 Chevrolet Silverado — Cylinder 7 Glow Plug Circuit Fault
- P0677 2018 Chevrolet Silverado — Cylinder 7 Glow Plug Circuit Fault
Frequently Asked Questions about P0677 Chevrolet Code
1. What does the OBDII code P0677 mean on a Chevrolet?
P0677 indicates a fault in the glow plug circuit for cylinder 7, meaning the glow plug or its related components may not be functioning correctly.
2. What are the symptoms of a P0677 code in a Chevrolet?
Common symptoms include difficulty starting the engine in cold weather, reduced engine performance, and an illuminated check engine light.
3. What causes the P0677 code on a Chevrolet?
Possible causes include a faulty glow plug, damaged wiring or connectors in the glow plug circuit, a bad glow plug control module, or corrosion within the circuit.
4. How do I diagnose a P0677 code on my Chevrolet?
Start by inspecting the glow plug for cylinder 7, checking for visible damage or wear. Next, test the wiring and connectors for continuity and ensure there are no signs of corrosion. Finally, test the glow plug control module.
5. Can a P0677 code cause engine damage if ignored?
While it may not cause immediate engine damage, ignoring the issue can lead to prolonged starting problems, increased emissions, and potential strain on the engine during cold starts.
6. How do I fix a P0677 code on a Chevrolet?
Repairs typically involve replacing the faulty glow plug, repairing damaged wiring or connectors, or replacing the glow plug control module if necessary.
7. What tools are needed to fix a P0677 code?
You may need a multimeter for testing electrical continuity, basic hand tools for replacing the glow plug, and an OBDII scanner to verify the code and clear it once repairs are complete.
8. Can I drive my Chevrolet with a P0677 code?
While the vehicle may still be drivable, cold starts could become challenging, and the issue should be addressed promptly to avoid further complications.
9. How much does it cost to repair a P0677 code on a Chevrolet?
The cost can vary, with glow plugs typically costing $20-$50 each, and labor ranging from $50 to $150, depending on the repair complexity and location.
10. Does replacing the glow plug always fix the P0677 code?
Not always. If the wiring, connectors, or control module are faulty, replacing the glow plug alone may not resolve the issue. A thorough diagnosis is essential.
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