AutoCodes – GMC – P066D 2014 GMC Sierra

P066D 2014 GMC Sierra Code - Cylinder 2 Glow Plug Control Circuit High Voltage

Quick Answer

n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #2 glow plug, Cylinder #2 glow plug harness is open or shorted, Cylinder #2 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: P066D 2014 GMC Sierra indicates Cylinder 2 Glow Plug Control Circuit High Voltage.
Common causes: Common causes include Faulty cylinder #2 glow plug, Cylinder #2 glow plug harness is open or shorted, Cylinder #2 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 178

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 P066D 2014 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 P066D 2014 GMC Sierra - Cylinder 2 Glow Plug Control Circuit High Voltage - AutoCodes.com — P066D 2014 GMC Sierra Code - Cylinder 2 Glow Plug Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P066D 2014 GMC Sierra?

Faulty cylinder #2 glow plug
Cylinder #2 glow plug harness is open or shorted
Cylinder #2 glow plug circuit poor electrical connection
Faulty Glow Plug Control Module

How to Fix the DTC P066D 2014 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 P066D 2014 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 P066D 2014 GMC Sierra code?

Need more information on how to fix the P066D 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P066D 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P066D 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P066D in a 2014 GMC Sierra related to the Cylinder 2 Glow Plug Control Circuit High Voltage issue?

- Common symptoms may include rough idling, decreased engine performance, decreased fuel efficiency, and illuminated check engine light.

2. What are the possible causes of the Cylinder 2 Glow Plug Control Circuit High Voltage code (P066D) in a 2014 GMC Sierra?

- Possible causes include a faulty glow plug, damaged wiring or connectors in the glow plug circuit, a malfunctioning glow plug control module, or issues with the engine control module (ECM).

3. How can I diagnose the Cylinder 2 Glow Plug Control Circuit High Voltage issue in my 2014 GMC Sierra?

- Diagnosis typically involves inspecting the glow plug and its connections, testing the glow plug control module, checking for continuity in the wiring, and using a scan tool to read the OBDII code and monitor system parameters.

4. Can driving with an active P066D code in a 2014 GMC Sierra cause further damage?

- Continuing to drive with the code may lead to poor engine performance and potential damage to other components, so it is advisable to address the issue promptly to prevent further issues.

5. How can I repair the Cylinder 2 Glow Plug Control Circuit High Voltage problem in a 2014 GMC Sierra?

- Repair options may include replacing the faulty glow plug, repairing or replacing damaged wiring or connectors, replacing the glow plug control module, or addressing any ECM-related issues.

6. Are there any preventative maintenance tips to avoid the P066D code in a 2014 GMC Sierra?

- Regularly inspecting and maintaining the glow plug system, checking for loose connections, and addressing any issues promptly can help prevent the Cylinder 2 Glow Plug Control Circuit High Voltage code.

7. Is it safe to continue driving my 2014 GMC Sierra with the check engine light on due to code P066D?

- While the vehicle may still be operable, it is recommended to have the issue diagnosed and repaired as soon as possible to prevent potential damage and ensure optimal performance.

8. How much does it typically cost to repair the Cylinder 2 Glow Plug Control Circuit High Voltage issue in a 2014 GMC Sierra?

- The cost of repair can vary depending on the specific cause of the issue, but it may involve parts and labor ranging from $100 to $500 or more, depending on the extent of the problem.

9. Can a DIY enthusiast fix the P066D code related to Cylinder 2 Glow Plug Control Circuit High Voltage in a 2014 GMC Sierra?

- Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to address simpler issues like replacing a glow plug or checking connections, but more complex repairs may require professional assistance.

10. Will resetting the OBDII codes clear the P066D code related to the Cylinder 2 Glow Plug Control Circuit High Voltage in a 2014 GMC Sierra?

- While resetting the codes may temporarily turn off the check engine light, it will not fix the underlying issue causing the code. It is important to diagnose and address the root cause of the problem to prevent it from recurring.