Engine-CodesGeneric – P066F

P066F Code - Cylinder 3 Glow Plug Control Circuit High Voltage

Quick Answer

The diagnostic trouble code P066F indicates a problem with the cylinder 3 glow plug control circuit, specifically detecting a high voltage condition. Common causes include Faulty glow plug control module, Short circuit in the wiring connected to the glow plug, Malfunctioning glow plug. 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
P066F indicates Cylinder 3 Glow Plug Control Circuit High Voltage.
Common causes
Common causes include Faulty glow plug control module, Short circuit in the wiring connected to the glow plug, Malfunctioning glow plug.
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.
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P066F Description

The diagnostic trouble code P066F indicates a problem with the cylinder 3 glow plug control circuit, specifically detecting a high voltage condition. Glow plugs are crucial components in diesel engines that help with cold starts by heating the combustion chamber. When the glow plug control circuit is experiencing high voltage, it can lead to issues with starting the engine, reduced fuel efficiency, and potential damage to other engine components.

OBDII Code P066F - Cylinder 3 Glow Plug Control Circuit High Voltage
P066F Code - Cylinder 3 Glow Plug Control Circuit High Voltage

Common Causes of P066F

  1. Faulty glow plug control module.
  2. Short circuit in the wiring connected to the glow plug.
  3. Malfunctioning glow plug.
  4. Corrosion or loose connections in the glow plug circuit.
  5. Issues with the engine control module (ECM) sending incorrect signals to the glow plug control circuit.

Symptoms of P066F

  1. Difficulty starting the engine, especially in cold weather.
  2. Reduced fuel efficiency due to incomplete combustion.
  3. Engine misfires or rough idling.
  4. Illumination of the check engine light on the dashboard.
  5. Increased exhaust emissions due to incomplete combustion.

How to Fix P066F

  1. Begin by verifying the diagnostic trouble code using a scan tool to ensure it is related to the cylinder 3 glow plug control circuit.
  2. Inspect the wiring connected to the glow plug for any signs of damage, corrosion, or loose connections. Repair or replace any faulty wiring.
  3. Test the glow plug control module for proper functioning and replace it if necessary.
  4. Check the glow plug itself for continuity and replace it if it is faulty.
  5. Clear the trouble code from the ECM and test the vehicle to ensure the issue has been resolved.

Cost to Fix P066F

The cost of repairing a cylinder 3 glow plug control circuit high voltage issue can vary depending on the specific cause of the problem. In general, the cost of parts such as a glow plug control module or a glow plug can range from $50 to $200. Labor costs at auto repair shops typically range from $80 to $150 per hour. The total repair cost for this issue could range from $150 to $500, depending on the extent of the repairs needed. It is recommended to consult with a qualified mechanic to get an accurate estimate based on your vehicle's make and model.

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Code P066F Information for Specific Makes

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.

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