P068E 2016 GMC Sierra Code - Cylinder 8 Glow Plug Control Circuit Low 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
- P068E 2016 GMC Sierra indicates Cylinder 8 Glow Plug Control Circuit Low 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 P068E 2016 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 P068E 2016 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 P068E 2016 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 P068E 2016 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 P068E 2016 GMC Sierra Code
1. What does OBDII code P068E mean on a 2016 GMC Sierra?
Code P068E indicates a problem with the Cylinder 8 Glow Plug Control Circuit, specifically a low voltage condition.
2. What are the common symptoms of code P068E in a 2016 GMC Sierra?
Symptoms may include hard starting in cold weather, reduced engine performance, a rough idle, and an illuminated check engine light.
3. What causes code P068E on a 2016 GMC Sierra?
Common causes include a faulty glow plug for cylinder 8, damaged wiring or connectors in the glow plug circuit, corrosion, or a malfunctioning glow plug control module.
4. How can I diagnose code P068E on my 2016 GMC Sierra?
Start by inspecting the glow plug for cylinder 8 and its wiring for damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuit.
5. Can I drive my 2016 GMC Sierra with code P068E?
While it might still be drivable, it’s not recommended to ignore this code as it can lead to harder starts and increased wear on the engine, especially in cold weather.
6. How do I fix code P068E on a 2016 GMC Sierra?
Repairs may include replacing the faulty glow plug, repairing or replacing damaged wiring, cleaning corroded connections, or replacing the glow plug control module if needed.
7. How much does it cost to fix code P068E on a 2016 GMC Sierra?
The repair cost depends on the issue, but replacing a glow plug typically costs $100-$300, including parts and labor. Wiring or control module repairs could cost more.
8. Can a weak battery cause code P068E on a 2016 GMC Sierra?
Yes, a weak or failing battery can contribute to low voltage in the glow plug circuit and may trigger this code.
9. How do I prevent code P068E from recurring on my 2016 GMC Sierra?
Regular maintenance, including checking the glow plug system, inspecting wiring for damage, and ensuring the battery is in good condition, can help prevent this code.
10. Does code P068E affect fuel efficiency on a 2016 GMC Sierra?
It can indirectly affect fuel efficiency if the engine struggles to start or runs inefficiently due to the malfunctioning glow plug system.
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