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Engine-Codes – GMC – P068F GMC

P068F GMC Code - Cylinder 8 Glow Plug Control Circuit High Voltage

Quick Answer

The P068F GMC code indicates a problem with the glow plug control circuit in cylinder 8 of the vehicle's engine. Common causes include Faulty glow plug in cylinder 8, Damaged wiring or connectors in the glow plug control circuit, Malfunctioning glow plug control module. 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
P068F GMC indicates Cylinder 8 Glow Plug Control Circuit High Voltage.
Common causes
Common causes include Faulty glow plug in cylinder 8, Damaged wiring or connectors in the glow plug control circuit, Malfunctioning glow plug control module.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P068F GMC Description

The P068F GMC code indicates a problem with the glow plug control circuit in cylinder 8 of the vehicle's engine. Glow plugs are devices used in diesel engines to heat the combustion chamber before starting the engine, especially in cold weather conditions. The glow plug control circuit is responsible for regulating the power supply to the glow plug, ensuring it reaches the necessary temperature for combustion.

OBDII Code P068F GMC - Cylinder 8 Glow Plug Control Circuit High Voltage
P068F GMC Code - Cylinder 8 Glow Plug Control Circuit High Voltage

Common Causes of P068F GMC

  1. Faulty glow plug in cylinder 8.
  2. Damaged wiring or connectors in the glow plug control circuit.
  3. Malfunctioning glow plug control module.
  4. Issues with the vehicle's power supply to the glow plug.

Symptoms of P068F GMC

  1. Difficulties starting the engine, especially in cold weather.
  2. Reduced engine performance and power.
  3. Increased fuel consumption.
  4. Engine misfires or rough idling.
  5. Illumination of the Check Engine Light on the dashboard.

How to Fix P068F GMC

  1. Begin by diagnosing the exact cause of the high voltage in the glow plug control circuit using a diagnostic scanner.
  2. Inspect the glow plug in cylinder 8 for any signs of damage or wear and replace if necessary.
  3. Check the wiring and connectors in the control circuit for any corrosion, breaks, or loose connections, and repair or replace as needed.
  4. Test the glow plug control module for proper functionality and replace if it is found to be faulty.
  5. Clear the diagnostic trouble codes from the vehicle's computer and test the engine to ensure the issue has been resolved.

Cost to Fix P068F GMC

The cost of repairing a cylinder 8 glow plug control circuit high voltage issue can vary depending on the specific cause of the problem and the parts required for the repair. On average, the repair costs can range from $200 to $500, including parts and labor. However, it is essential to note that labor rates at auto repair shops can vary significantly, so it is advisable to check with local shops for a more accurate estimate.

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Information for Specific GMC Models

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 P068F GMC Code

1. What does the OBDII code P068F mean for a GMC vehicle?

P068F indicates an issue with the Cylinder 8 Glow Plug Control Circuit, specifically detecting high voltage, which may affect engine performance and starting in cold conditions.

2. What are the common symptoms of the P068F code on GMC vehicles?

Symptoms may include difficulty starting the engine in cold weather, rough idling, reduced fuel efficiency, and the check engine light being illuminated.

3. What causes the P068F code to appear?

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

4. Can I drive my GMC with the P068F code?

While the vehicle may still be drivable, ignoring the code can lead to starting issues, especially in colder temperatures, and may result in further engine damage over time.

5. How is the P068F code diagnosed?

A mechanic will use a scan tool to confirm the code, inspect the Cylinder 8 glow plug, check the wiring and connectors for damage, and test the glow plug control module for proper functionality.

6. How do I fix the P068F code on my GMC?

Repairs may involve replacing the faulty glow plug, repairing or replacing damaged wiring or connectors, or replacing the glow plug control module if needed.

7. How much does it cost to repair the P068F code on a GMC?

The cost can vary, but replacing a glow plug typically ranges from $100 to $300, while a glow plug control module replacement may cost $200 to $500, including parts and labor.

8. Can a faulty ECM cause the P068F code?

Yes, in rare cases, a malfunctioning Engine Control Module (ECM) can incorrectly regulate the voltage in the circuit, triggering the P068F code.

9. How can I prevent the P068F code from occurring?

Regular maintenance, including inspecting glow plugs and their wiring for wear or damage, can help prevent issues related to the P068F code.

10. Is the P068F code specific to GMC vehicles?

While P068F can appear on other diesel vehicles with a similar glow plug system, its specific diagnosis and repair may vary depending on the make and model.

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