P068E 2018 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 2018 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 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 P068E 2018 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 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 P068E 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 P068E 2018 GMC Sierra code?
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Frequently Asked Questions about P068E 2018 GMC Sierra Code
1. What are the common symptoms of OBDII code P068E in a 2018 GMC Sierra related to the Cylinder 8 Glow Plug Control Circuit Low Voltage?
- Common symptoms may include rough idling, reduced engine performance, and illuminated check engine light.
2. What are the possible causes of the Cylinder 8 Glow Plug Control Circuit Low Voltage code (P068E) in a 2018 GMC Sierra?
- Potential causes can be a faulty glow plug, damaged wiring or connectors, a malfunctioning glow plug control module, or issues with the ECM.
3. How can I diagnose the Cylinder 8 Glow Plug Control Circuit Low Voltage issue in my 2018 GMC Sierra?
- Diagnostic steps may include checking the glow plug and its connections, testing the glow plug control module, inspecting wiring for damage, and scanning the ECM for related fault codes.
4. Can a DIY enthusiast repair the P068E code in a 2018 GMC Sierra, or should it be done by a professional mechanic?
- While some basic checks like inspecting connections can be done by DIYers, diagnosing and repairing complex issues related to the glow plug circuit may require professional expertise.
5. Are there any specific repair tips for addressing the Cylinder 8 Glow Plug Control Circuit Low Voltage code in a 2018 GMC Sierra?
- Ensure all connections are secure, use a multimeter to test the glow plug resistance, and consider consulting the vehicle's service manual for detailed troubleshooting steps.
6. Will driving with the P068E code present in a 2018 GMC Sierra cause any further damage to the vehicle?
- Continuing to drive with this code may lead to reduced engine efficiency and potential damage to the glow plug system over time, so it's advisable to address the issue promptly.
7. How can I reset the check engine light after repairing the Cylinder 8 Glow Plug Control Circuit Low Voltage code in my 2018 GMC Sierra?
- The check engine light can be reset using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes to clear the stored fault codes.
8. Is the P068E code in a 2018 GMC Sierra a common issue, or is it more likely to be a rare occurrence?
- While not as common as some other OBDII codes, issues related to the glow plug control circuit can occur, especially in vehicles with high mileage or poor maintenance history.
9. Are there any preventive maintenance steps that can help avoid the Cylinder 8 Glow Plug Control Circuit Low Voltage code in a 2018 GMC Sierra?
- Regularly inspecting and replacing glow plugs as per the manufacturer's recommended intervals, along with keeping the electrical system well-maintained, can help prevent such issues.
10. Can extreme weather conditions or environmental factors contribute to triggering the P068E code in a 2018 GMC Sierra?
- Yes, extreme cold temperatures or water exposure can potentially affect the glow plug system, leading to issues like low voltage in the control circuit and triggering the P068E code.
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