P066C 2018 GMC Sierra Code - Cylinder 2 Glow Plug Control Circuit Low Voltage
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #2 glow plug, Cylinder #2 glow plug harness is open or shorted, Cylinder #2 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
- P066C 2018 GMC Sierra indicates Cylinder 2 Glow Plug Control Circuit Low Voltage.
- Common causes
- Common causes include Faulty cylinder #2 glow plug, Cylinder #2 glow plug harness is open or shorted, Cylinder #2 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 P066C 2018 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 P066C 2018 GMC Sierra?
- Faulty cylinder #2 glow plug
- Cylinder #2 glow plug harness is open or shorted
- Cylinder #2 glow plug circuit poor electrical connection
- Faulty Glow Plug Control Module
How to Fix the DTC P066C 2018 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 P066C 2018 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 P066C 2018 GMC Sierra code?
Need more information on how to fix the P066C 2018 GMC Sierra code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P066C 2018 GMC Sierra code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P066C 2018 GMC Sierra Code
1. What are the common symptoms of OBDII code P066C on a 2018 GMC Sierra related to the Cylinder 2 Glow Plug Control Circuit Low Voltage?
The common symptoms may include rough idling, decreased engine performance, and an illuminated check engine light.
2. What are the possible causes of OBDII code P066C in a 2018 GMC Sierra, indicating an issue with the Cylinder 2 Glow Plug Control Circuit Low Voltage?
Possible causes may include a faulty glow plug, damaged wiring or connectors in the glow plug circuit, or a malfunctioning glow plug control module.
3. How can I diagnose the issue related to OBDII code P066C in my 2018 GMC Sierra's Cylinder 2 Glow Plug Control Circuit Low Voltage?
Diagnosis typically involves inspecting the glow plug, checking the wiring and connectors for damage, and testing the glow plug control module for proper functioning.
4. Can driving with OBDII code P066C in a 2018 GMC Sierra, signaling a problem with the Cylinder 2 Glow Plug Control Circuit Low Voltage, cause further damage to the vehicle?
Continuing to drive with this issue may lead to decreased fuel efficiency, potential engine misfires, and further damage to the glow plug system.
5. How can I repair OBDII code P066C on a 2018 GMC Sierra associated with the Cylinder 2 Glow Plug Control Circuit Low Voltage?
Repair methods may include replacing the faulty glow plug, repairing or replacing damaged wiring or connectors, or installing a new glow plug control module.
6. Is it possible to clear the OBDII code P066C on a 2018 GMC Sierra without addressing the underlying issue with the Cylinder 2 Glow Plug Control Circuit Low Voltage?
Clearing the code without fixing the problem may temporarily turn off the check engine light, but the issue will persist and likely trigger the code again.
7. Are there any preventive measures to avoid encountering OBDII code P066C in a 2018 GMC Sierra related to the Cylinder 2 Glow Plug Control Circuit Low Voltage?
Regular maintenance checks, including inspecting the glow plug system and related components, can help prevent issues leading to this trouble code.
8. How long does it typically take to repair OBDII code P066C on a 2018 GMC Sierra associated with the Cylinder 2 Glow Plug Control Circuit Low Voltage?
The repair time can vary depending on the exact cause of the issue and the availability of parts, but it may take a few hours to a full day for a professional mechanic to address the problem.
9. Can a DIY enthusiast with basic automotive knowledge fix OBDII code P066C in a 2018 GMC Sierra related to the Cylinder 2 Glow Plug Control Circuit Low Voltage?
While some aspects of the repair may be tackled by DIY enthusiasts, diagnosing and fixing electrical issues like those related to glow plug circuits may require specialized tools and expertise.
10. How much does it cost to repair OBDII code P066C on a 2018 GMC Sierra, signaling an issue with the Cylinder 2 Glow Plug Control Circuit Low Voltage?
The cost of repair can vary based on the specific components that need replacement or repair, with potential expenses ranging from a few hundred to over a thousand dollars, including parts and labor.
Discuss the causes and fixes for P066C 2018 GMC Sierra OBDII Code
Code P066C 2018 GMC Sierra 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.
