AutoCodes – GMC – P0676 2015 GMC Sierra

P0676 2015 GMC Sierra Code - Cylinder 6 Glow Plug Circuit Fault

Quick Answer

n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #6 glow plug, Cylinder #6 glow plug harness is open or shorted, Cylinder #6 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: P0676 2015 GMC Sierra indicates Cylinder 6 Glow Plug Circuit Fault.
Common causes: Common causes include Faulty cylinder #6 glow plug, Cylinder #6 glow plug harness is open or shorted, Cylinder #6 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.

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Code Popularity 198

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0676 2015 GMC Sierra Description

n the diesel engine, air alone is compressed in the cylinder. Then, after the air has been compressed, a charge of fuel is sprayed into the cylinder and ignition occurs, due to the heat of compression. Eight glow plugs are used as an aid to starting.
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.

OBDII Code P0676 2015 GMC Sierra - Cylinder 6 Glow Plug Circuit Fault - AutoCodes.com — P0676 2015 GMC Sierra Code - Cylinder 6 Glow Plug Circuit Fault

What does this mean?

What are the Possible Causes of the DTC P0676 2015 GMC Sierra?

Faulty cylinder #6 glow plug
Cylinder #6 glow plug harness is open or shorted
Cylinder #6 glow plug circuit poor electrical connection
Faulty Glow Plug Control Module (GPCM)

How to Fix the DTC P0676 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 P0676 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.

Need more information about the P0676 2015 GMC Sierra code?

Need more information on how to fix the P0676 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0676 2015 GMC Sierra Code

1. What does OBDII code P0676 on a 2015 GMC Sierra indicate?

- This code refers to a Cylinder 6 Glow Plug Circuit Fault.

2. What are some common symptoms of a Cylinder 6 Glow Plug Circuit Fault in a 2015 GMC Sierra?

- Common symptoms include hard starting, rough idling, and decreased engine performance.

3. What can cause the Cylinder 6 Glow Plug Circuit Fault in a 2015 GMC Sierra?

- Possible causes include a faulty glow plug, wiring issues, or a problem with the glow plug control module.

4. How can I diagnose a Cylinder 6 Glow Plug Circuit Fault in my 2015 GMC Sierra?

- A diagnostic scan tool can be used to read the OBDII code and pinpoint the exact issue with the glow plug circuit.

5. Can I still drive my 2015 GMC Sierra with a Cylinder 6 Glow Plug Circuit Fault?

- It is not recommended to drive the vehicle with this fault as it can lead to further engine damage.

6. How can I repair a Cylinder 6 Glow Plug Circuit Fault in my 2015 GMC Sierra?

- The faulty glow plug or any damaged wiring should be replaced to resolve the issue.

7. Is it possible to reset the OBDII code P0676 in a 2015 GMC Sierra after the repair?

- Yes, after the repair is completed, the code can be cleared using a diagnostic scan tool.

8. Will a Cylinder 6 Glow Plug Circuit Fault cause the check engine light to illuminate in a 2015 GMC Sierra?

- Yes, this fault will trigger the check engine light to come on in the vehicle.

9. How important is it to address a Cylinder 6 Glow Plug Circuit Fault in a 2015 GMC Sierra promptly?

- It is crucial to address this issue promptly to prevent further damage to the engine and ensure optimal performance.

10. Can a DIY enthusiast with basic mechanical skills repair a Cylinder 6 Glow Plug Circuit Fault in a 2015 GMC Sierra?

- While some DIY enthusiasts may be able to replace a glow plug, diagnosing and repairing wiring or module issues may require professional assistance.