P0672 Code: Complete DIY Repair Guide

The P0672 trouble code is a diagnostic trouble code (DTC) that indicates an issue with the glow plug circuit for cylinder number two in diesel engines. This code is triggered when the Powertrain Control Module (PCM) detects a malfunction in the glow plug circuit, which is crucial for preheating the combustion chamber before starting the engine. If left unresolved, this issue can lead to difficulties in starting the engine, especially in cold weather, and may result in decreased engine performance.

Symptoms of P0672 Code

When dealing with a P0672 code, vehicle owners may experience various symptoms, including:

• Difficulty Starting: The engine may struggle to start, especially in cold conditions.
• Illuminated Check Engine Light: The check engine light will be activated on the dashboard.
• Reduced Engine Power: There may be a noticeable drop in power until the engine warms up.
• Engine Hesitation: The engine may hesitate or misfire during acceleration.
• No Preheat Indicator: The preheat light may not function correctly or turn off prematurely.

These symptoms can vary based on the severity of the issue and whether other related codes are present.

Technical Explanation of P0672 Code

The P0672 code specifically relates to the glow plug circuit for cylinder number two. Glow plugs are essential components in diesel engines as they heat the air in the combustion chamber to facilitate ignition during cold starts. A malfunction in this circuit can stem from various issues, such as:

• Faulty Glow Plug: If the glow plug itself is defective, it will not heat properly, leading to difficulties during starting.
• Wiring Issues: Damaged wires or poor connections can disrupt the flow of electricity necessary for the glow plug to operate effectively.
• Control Module Failures: The glow plug control module regulates power to the glow plugs. If it fails, it may not provide adequate voltage for operation.
• PCM Malfunction: An issue with the PCM can lead to incorrect readings and operations within the glow plug circuit.

Step-by-Step Diagnosis of P0672 Code

Diagnosing a P0672 code involves several steps:

1. Visual Inspection:

• Start by visually inspecting the wiring harness connected to cylinder two’s glow plug for any signs of wear, damage, or corrosion.
• Check all connectors for secure connections and any signs of electrical shorts.

1. Use a Multimeter:

• Disconnect the glow plug connector and test its resistance using a multimeter. A healthy glow plug should have a resistance between 0.5 and 2 ohms.
• If resistance is outside this range, replace the glow plug.

1. Check Wiring Continuity:

• Test continuity from the glow plug connector back to the control module. Look for breaks or shorts in wiring.

1. Test Glow Plug Control Module:

• If wiring and plugs are functioning correctly, test the glow plug control module for proper operation.
• Ensure it receives power and ground signals as specified by manufacturer guidelines.

1. Scan for Additional Codes:

• Use an OBD-II scanner to check for any additional trouble codes that may provide further insight into related issues.

Solution Methods for P0672 Code

Once diagnosed, there are several potential solutions depending on the identified cause:

• Replace Faulty Glow Plug:
• If testing reveals that cylinder two’s glow plug is defective, replace it with a new one.
• Repair Wiring Issues:
• Fix any damaged wiring or connectors found during inspection. Ensure all connections are clean and secure.
• Replace Control Module:
• If the glow plug control module is faulty, replace it according to manufacturer specifications. Ensure proper programming if required.
• PCM Reprogramming or Replacement:
• In rare cases where PCM malfunction is suspected, reprogramming or replacement may be necessary. Consult with a professional technician for this process.

Cost Estimates

The cost of repairs associated with a P0672 code can vary widely based on location and vehicle make/model:

• Glow Plug Replacement: $100-$300 (parts and labor)
• Wiring Repairs: $50-$150 (depending on extent of damage)
• Control Module Replacement: $200-$600 (parts and labor)
• PCM Reprogramming/Replacement: $500-$1500 (varies significantly based on vehicle)

Warnings and Recommendations

• Always ensure that you disconnect the battery before working on electrical components to avoid shorts or shocks.
• If you are unfamiliar with automotive electrical systems or lack experience in diagnostics, it is highly recommended to seek professional assistance to avoid further damage or safety hazards.
• Regular maintenance checks can prevent issues with glow plugs and circuits; consider incorporating these into your vehicle’s service schedule.

Frequently Asked Questions About P0672

• What does P0672 mean?
  The P0672 code indicates a malfunction in the glow plug circuit for cylinder number two in diesel engines.
• Can I drive my car with a P0672 code?
  While it may still start and run, driving with this code can lead to poor performance and starting issues, especially in cold weather.
• How serious is a P0672 code?
  This code can lead to significant starting problems and reduced engine efficiency; addressing it promptly is advisable.
• What tools do I need to diagnose a P0672 code?
  A multimeter for electrical testing and an OBD-II scanner for reading codes are essential tools.
• How much does it cost to fix a P0672 code?
  The cost ranges from $100 for simple repairs like replacing a glow plug to over $1000 if major components like PCM need replacement.
• Can I replace a glow plug myself?
  If you have basic mechanical skills and tools, replacing a glow plug can be done as a DIY project.
• What should I do if I can’t find the problem?
  If diagnostics do not reveal clear issues, consider consulting with an experienced mechanic.
• Are there any preventative measures?
  Regular maintenance checks on your diesel engine’s electrical systems can help prevent future issues with glow plugs.

In conclusion, understanding and addressing the P0672 trouble code is crucial for maintaining your diesel engine’s performance and reliability. By following proper diagnostic procedures and solutions outlined above, vehicle owners can effectively manage this common issue. Always prioritize safety and consult professionals when necessary to ensure optimal vehicle operation.