P068D 2015 GMC Sierra Code - Cylinder 7 Glow Plug Control Circuit High Voltage
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
- P068D 2015 GMC Sierra indicates Cylinder 7 Glow Plug Control Circuit High Voltage.
- 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 P068D 2015 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 P068D 2015 GMC Sierra?
- 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
How to Fix the DTC P068D 2015 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 P068D 2015 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 P068D 2015 GMC Sierra Code
What does the OBDII code P068D mean for a 2015 GMC Sierra?
Code P068D indicates high voltage in the glow plug control circuit for cylinder 7, often related to the glow plug module or wiring issues.
What are the symptoms of code P068D in a 2015 GMC Sierra?
Symptoms may include difficulty starting the engine, poor cold-weather performance, or an illuminated check engine light.
What causes the P068D code in a 2015 GMC Sierra?
Common causes include a faulty glow plug, damaged wiring, loose connections, or a malfunctioning glow plug control module.
Can I drive my 2015 GMC Sierra with code P068D?
While the vehicle may still be operable, driving with this code can lead to poor engine performance and potential damage in cold conditions.
How do I diagnose the P068D code in a 2015 GMC Sierra?
Diagnosis typically involves inspecting the glow plug, wiring, connectors, and testing the glow plug control module for proper function.
How do I fix the P068D code on a 2015 GMC Sierra?
Repair may involve replacing the glow plug for cylinder 7, repairing damaged wiring, or replacing the glow plug control module if faulty.
How much does it cost to repair code P068D on a 2015 GMC Sierra?
Repair costs can vary but typically range from $150 to $300 depending on whether the glow plug or module needs replacement.
Can a bad glow plug cause the P068D code in a 2015 GMC Sierra?
Yes, a faulty glow plug can cause high voltage issues in the control circuit, triggering the P068D code.
Will clearing the P068D code fix the problem on my 2015 GMC Sierra?
Clearing the code may temporarily turn off the check engine light, but the underlying issue must be repaired to prevent the code from returning.
How can I prevent the P068D code in my 2015 GMC Sierra?
Regular inspection of the glow plugs, wiring, and connections during routine maintenance can help prevent issues leading to this code.
Discuss the causes and fixes for P068D 2015 GMC Sierra OBDII Code
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