P068F 2017 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 2017 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 2017 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 2017 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 2017 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 2017 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.
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Frequently Asked Questions about P068F 2017 GMC Sierra Code
What does the OBDII code P068F mean on a 2017 GMC Sierra?
P068F indicates a high voltage issue in the Cylinder 8 Glow Plug Control Circuit, typically related to the glow plug system responsible for aiding engine starting in cold conditions.
What are the common symptoms of code P068F on a 2017 GMC Sierra?
Symptoms may include difficulty starting the engine in cold weather, an illuminated check engine light, and reduced fuel efficiency.
What causes the P068F code on a 2017 GMC Sierra?
Common causes include a faulty glow plug, damaged wiring or connectors in the glow plug circuit, a malfunctioning glow plug control module, or a software issue in the powertrain control module (PCM).
How can I diagnose the P068F code on my 2017 GMC Sierra?
Diagnosis involves checking the Cylinder 8 glow plug for continuity, inspecting wiring and connectors for damage, and testing the glow plug control module for proper operation.
Can I still drive my 2017 GMC Sierra with a P068F code?
While the vehicle may still run, prolonged driving with this code can lead to harder starts in cold weather and potential damage to the glow plug system. It's best to address the issue promptly.
How do I fix the P068F code on a 2017 GMC Sierra?
Repairs may involve replacing the faulty glow plug, repairing damaged wiring or connectors, or replacing the glow plug control module if it is defective.
Is the P068F code covered under warranty for a 2017 GMC Sierra?
This depends on your vehicle's warranty terms. Check with your GMC dealer to see if the glow plug system components are covered under your powertrain or emissions warranty.
How much does it cost to fix the P068F code on a 2017 GMC Sierra?
Repair costs vary but typically range from $100 to $300 for parts and labor, depending on whether the glow plug, wiring, or control module needs to be replaced.
Can a weak battery cause the P068F code on a 2017 GMC Sierra?
Yes, a weak or failing battery can cause voltage irregularities that may trigger the P068F code. Ensure the battery is in good condition before diagnosing further.
Do I need special tools to fix the P068F code on my 2017 GMC Sierra?
Basic tools like a multimeter can help check voltage and continuity. In some cases, an OBDII scanner capable of reading live data may be needed for more advanced diagnostics.
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