P068F 2014 GMC Sierra Code - Cylinder 8 Glow Plug Control Circuit High Voltage
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #8 glow plug, Cylinder #8 glow plug harness is open or shorted, Cylinder #8 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
- P068F 2014 GMC Sierra indicates Cylinder 8 Glow Plug Control Circuit High Voltage.
- Common causes
- Common causes include Faulty cylinder #8 glow plug, Cylinder #8 glow plug harness is open or shorted, Cylinder #8 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 P068F 2014 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 P068F 2014 GMC Sierra?
- Faulty cylinder #8 glow plug
- Cylinder #8 glow plug harness is open or shorted
- Cylinder #8 glow plug circuit poor electrical connection
- Faulty Glow Plug Control Module
How to Fix the DTC P068F 2014 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 P068F 2014 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 P068F 2014 GMC Sierra code?
Need more information on how to fix the P068F 2014 GMC Sierra code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P068F 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P068F 2014 GMC Sierra Code
1. What does the OBDII code P068F mean on a 2014 GMC Sierra?
P068F refers to an issue with the glow plug control circuit, specifically in cylinder 8, where the voltage is reading higher than expected.
2. What are the common symptoms of a P068F code on a 2014 GMC Sierra?
Symptoms may include difficulty starting in cold weather, rough idling, reduced engine performance, and an illuminated check engine light.
3. What causes the P068F code on a 2014 GMC Sierra?
The code can be triggered by a faulty glow plug, a damaged glow plug control module, corroded wiring or connectors, or a short circuit in the control circuit.
4. Can I drive my 2014 GMC Sierra with a P068F code?
While the truck may still run, driving with this code can lead to poor cold starts and potential engine damage over time if not addressed.
5. How do I diagnose the P068F code on my 2014 GMC Sierra?
Use an OBDII scanner to confirm the code, then visually inspect the glow plug, wiring, and control module for damage or corrosion. Test the voltage and resistance of the circuit if necessary.
6. How do I fix the P068F code on a 2014 GMC Sierra?
Repairs may include replacing the faulty glow plug, repairing damaged wiring or connectors, or replacing the glow plug control module.
7. How much does it cost to repair a P068F code on a 2014 GMC Sierra?
Repair costs can range from $100 to $500, depending on whether you need to replace a glow plug, repair wiring, or replace the control module.
8. Can a bad battery cause the P068F code on a 2014 GMC Sierra?
Yes, a weak or failing battery can affect the voltage supplied to the glow plug system, potentially triggering this code.
9. Will clearing the P068F code fix the problem on my 2014 GMC Sierra?
Clearing the code will remove it temporarily, but the issue will likely return unless the underlying cause is repaired.
10. How can I prevent the P068F code from occurring on my 2014 GMC Sierra?
Regularly inspect and maintain the glow plug system, including checking for corrosion, damaged wiring, and ensuring the battery is in good condition.
Discuss the causes and fixes for P068F 2014 GMC Sierra OBDII Code
Code P068F 2014 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.
