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Engine-Codes – Generic – P066C

P066C Code - Cylinder 2 Glow Plug Control Circuit Low Voltage

Quick Answer

The P066C diagnostic trouble code (DTC) refers to an issue with the Cylinder 2 Glow Plug Control Circuit, specifically indicating that there is low voltage present in the circuit. Common causes include Faulty glow plug, Damaged wiring or connectors in the control circuit, Malfunctioning glow plug relay. 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
P066C indicates Cylinder 2 Glow Plug Control Circuit Low Voltage.
Common causes
Common causes include Faulty glow plug, Damaged wiring or connectors in the control circuit, Malfunctioning glow plug relay.
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 11, 2024
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Code P066C Description

The P066C diagnostic trouble code (DTC) refers to an issue with the Cylinder 2 Glow Plug Control Circuit, specifically indicating that there is low voltage present in the circuit. Glow plugs are essential components in diesel engines as they help heat the combustion chamber, especially during cold starts. When there is low voltage in the control circuit of the glow plug for Cylinder 2, it can lead to difficulties in starting the engine, reduced engine performance, increased emissions, and potential long-term damage to the engine if left unaddressed.

OBDII Code P066C - Cylinder 2 Glow Plug Control Circuit Low Voltage
P066C Code - Cylinder 2 Glow Plug Control Circuit Low Voltage

Common Causes of P066C

  1. Faulty glow plug
  2. Damaged wiring or connectors in the control circuit
  3. Malfunctioning glow plug relay
  4. Issues with the engine control module (ECM)

Symptoms of P066C

  1. Difficulty starting the engine, especially in cold weather
  2. Rough idling or misfires
  3. Decreased fuel efficiency
  4. Illumination of the check engine light
  5. Increased emissions

How to Fix P066C

  1. Begin by inspecting the glow plug for Cylinder 2 and test its functionality. Replace the glow plug if it is found to be faulty.
  2. Check the wiring and connectors in the control circuit for any damage or corrosion. Repair or replace as necessary.
  3. Test the glow plug relay to ensure it is functioning correctly. Replace if faulty.
  4. If the issue persists, diagnose the ECM for any faults related to the glow plug control circuit and address accordingly.
  5. Clear the DTC and test the vehicle to ensure the issue has been resolved.

Cost to Fix P066C

The typical repair costs for addressing a Cylinder 2 Glow Plug Control Circuit Low Voltage issue can vary depending on the specific cause of the problem and the make and model of the vehicle. Generally, the cost of replacing a glow plug ranges from $50 to $150 per plug, while the cost of labor can be around $100 to $200. If additional components such as wiring or the glow plug relay need replacement, the total cost could increase. It is advisable to consult with a professional mechanic to get an accurate estimate based on your vehicle's individual needs.

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Code P066C 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.

Frequently Asked Questions about P066C Code

1. What are the common symptoms of OBDII code P066C (Cylinder 2 Glow Plug Control Circuit Low Voltage)?

Common symptoms include difficulty starting the engine, rough idling, decreased fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P066C?

Possible causes may include a faulty glow plug, damaged wiring or connectors in the glow plug circuit, a defective glow plug control module, or a problem with the engine control module.

3. How can I diagnose the issue related to OBDII code P066C?

To diagnose the issue, you can use a diagnostic scanner to retrieve the trouble codes, inspect the glow plug and its connections, check the voltage in the circuit, and perform a continuity test on the wiring.

4. Can I continue driving with OBDII code P066C present?

It is not recommended to continue driving with this code present, as it can lead to poor engine performance, potential damage to other components, and increased emissions. It's best to address the issue promptly.

5. How can I repair OBDII code P066C?

Repair options may include replacing the faulty glow plug, repairing or replacing damaged wiring or connectors, replacing the glow plug control module, or reprogramming the engine control module if needed.

6. Is it necessary to clear the OBDII code P066C after making repairs?

Yes, it is important to clear the code using a diagnostic scanner after making repairs. This will reset the check engine light and allow you to monitor if the issue has been successfully resolved.

7. Are there any preventative maintenance tips to avoid OBDII code P066C in the future?

To prevent this code from reoccurring, it is recommended to follow the manufacturer's recommended maintenance schedule, regularly inspect the glow plug system, and address any issues promptly.

8. Can a DIY enthusiast fix OBDII code P066C at home?

Depending on your level of experience and access to tools, some DIY enthusiasts may be able to address OBDII code P066C at home. However, if you are unsure or lack the necessary expertise, it's best to consult a professional mechanic.

9. Will OBDII code P066C affect vehicle safety?

While OBDII code P066C is more related to engine performance and emissions, unresolved issues can indirectly impact vehicle safety if left unaddressed. It's best to resolve the problem to maintain overall vehicle health.

10. How long does it typically take to repair OBDII code P066C?

The repair time for OBDII code P066C can vary depending on the specific cause of the issue, availability of parts, and the expertise of the person performing the repair. In general, it may take a few hours to a full day to complete the repair.

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