P06C8 GMC Code - Cylinder 4 Glow Plug Incorrect
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #1 glow plug, Cylinder #1 glow plug harness is open or shorted, Cylinder #1 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
- P06C8 GMC indicates Cylinder 4 Glow Plug Incorrect.
- Common causes
- Common causes include Faulty cylinder #1 glow plug, Cylinder #1 glow plug harness is open or shorted, Cylinder #1 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 P06C8 GMC 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. A Diagnostic Trouble Code (DTC) will be set if the Glow Plug resistance is not within a calibrated range.
What are the Possible Causes of the DTC P06C8 GMC?
- Faulty cylinder #1 glow plug
- Cylinder #1 glow plug harness is open or shorted
- Cylinder #1 glow plug circuit poor electrical connection
- Faulty Glow Plug Control Module
How to Fix the DTC P06C8 GMC?
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 P06C8 GMC 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 P06C8 GMC code?
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Need Help with the Code?
Get the P06C8 GMC code diagnosed by a professional: Find a repair shop in your area
Information for Specific GMC Models
- P06C8 2014 GMC Sierra — Cylinder 4 Glow Plug Incorrect
- P06C8 2015 GMC Sierra — Cylinder 4 Glow Plug Incorrect
- P06C8 2016 GMC Sierra — Cylinder 4 Glow Plug Incorrect
- P06C8 2017 GMC Sierra — Cylinder 4 Glow Plug Incorrect
- P06C8 2018 GMC Sierra — Cylinder 4 Glow Plug Incorrect
Frequently Asked Questions about P06C8 GMC Code
1. What does the OBDII code P06C8 mean on a GMC?
The P06C8 code indicates that there is an issue with the glow plug in cylinder 4, typically due to an incorrect or faulty performance detected by the engine control module (ECM).
2. What are the common symptoms of the P06C8 code?
Symptoms may include difficulty starting the engine in cold weather, rough idling, reduced fuel efficiency, and the illumination of the check engine light.
3. What causes the P06C8 code to appear on a GMC vehicle?
Common causes include a faulty glow plug in cylinder 4, wiring or connector issues related to the glow plug circuit, a malfunctioning glow plug control module, or an ECM software fault.
4. How do I diagnose the P06C8 code on my GMC?
Diagnosis involves inspecting the glow plug in cylinder 4, checking the wiring and connectors for damage or corrosion, testing the glow plug control module, and using a scan tool to verify the fault.
5. Can I drive my GMC with the P06C8 code?
While it may be possible to drive, it's not recommended, especially in cold weather, as the engine may have trouble starting or operating efficiently.
6. How can I fix the P06C8 code on my GMC?
Repairs may include replacing the faulty glow plug, repairing or replacing damaged wiring or connectors, or replacing the glow plug control module if necessary.
7. How much does it cost to fix the P06C8 code on a GMC?
The cost can vary, but replacing a glow plug typically ranges from $100 to $300, depending on labor costs and the specific vehicle model.
8. Can a faulty glow plug cause engine damage if the P06C8 code persists?
A faulty glow plug itself is unlikely to cause engine damage, but persistent starting issues and unburned fuel can lead to other problems over time.
9. Do I need special tools to fix the P06C8 code on a GMC?
Yes, you may need a diagnostic scan tool to access the fault code, a multimeter to test the circuit, and appropriate tools to remove and replace the glow plug.
10. How can I prevent the P06C8 code from occurring again?
Regular maintenance, including checking glow plugs and related wiring, can help prevent this issue. Using high-quality replacement parts also ensures longer-lasting performance.
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