P0672 Code: Step-by-Step Repair

The P0672 trouble code is a diagnostic trouble code (DTC) that indicates an issue with the glow plug circuit of cylinder 2 in diesel engines. Glow plugs are essential components in diesel engines, designed to preheat the combustion chamber to facilitate starting, especially in cold weather. When the powertrain control module (PCM) detects a malfunction in the glow plug circuit for cylinder 2, it triggers the P0672 code, which can lead to starting difficulties and reduced engine performance.

Symptoms of P0672 Code

When dealing with a P0672 code, vehicle owners may experience several symptoms, which can vary based on the severity of the issue:

• Hard Starting or No Start: The engine may struggle to start, particularly in cold weather.
• Reduced Power: There may be a noticeable lack of power until the engine warms up sufficiently.
• Engine Hesitation: During acceleration, the engine might hesitate or miss due to inadequate heating of the combustion chamber.
• Check Engine Light: The illumination of the check engine light is common when this code is triggered.
• No Preheat Indicator: The preheat light may fail to activate or turn off, indicating potential issues with the glow plug system.

Technical Explanation

The P0672 code specifically refers to a problem within the glow plug circuit for cylinder 2. Glow plugs operate by heating up and providing warmth to the combustion chamber, allowing for efficient fuel ignition in diesel engines. When there is a failure in this circuit—whether due to a faulty glow plug, damaged wiring, or issues with the control module—the PCM will log a P0672 code.

How Glow Plugs Work

Glow plugs are typically made of a metal rod that heats up when electricity flows through it. This heat is crucial for starting diesel engines, especially under cold conditions where fuel may not ignite easily. If the glow plug does not reach the necessary temperature due to circuit issues, it can lead to hard starts and poor engine performance.

Step-by-Step Diagnosis

Diagnosing a P0672 code involves several steps:

1. Visual Inspection: Begin by visually inspecting the wiring harness and connectors associated with cylinder 2’s glow plug for any signs of damage or corrosion.
2. Use a Multimeter: Measure resistance across the glow plug. A healthy glow plug typically shows resistance between 0.5 and 2.0 ohms. If it falls outside this range, replacement is necessary.
3. Check Wiring Continuity: Inspect the wiring from the PCM to the glow plug for continuity. Any breaks or shorts can lead to circuit failures.
4. Test Glow Plug Control Module: If applicable, test the control module for proper operation and ensure it’s receiving power and ground signals as expected.
5. Clear Codes and Test Drive: After repairs or replacements, clear any codes using an OBD-II scanner and take the vehicle for a test drive to see if the issue reoccurs.

Solution Methods

Depending on what you find during diagnosis, here are potential solutions:

• Replace Faulty Glow Plug: If testing reveals that cylinder 2’s glow plug is defective, replace it with a new one that meets manufacturer specifications.
• Repair Wiring Issues: If damaged wiring or connectors are found, repair or replace them as needed to restore proper function.
• Replace Glow Plug Control Module: If testing indicates that the control module is malfunctioning, replace it according to manufacturer guidelines.
• Update PCM Software: In some cases, software updates from manufacturers can resolve underlying issues related to DTCs like P0672.

Cost Estimates

The cost of repairs can vary widely based on location and vehicle type:

• Glow Plug Replacement: $50 – $150 per glow plug (parts only).
• Wiring Repairs: $100 – $300 depending on labor rates and extent of damage.
• Control Module Replacement: $200 – $600 depending on whether it’s integrated into other systems.

Warnings and Recommendations

• Always ensure that you have disconnected the battery before working on electrical components to avoid short circuits or shocks.
• If you’re unfamiliar with automotive repairs or diagnostics, consider seeking professional assistance to avoid costly mistakes.
• Regular maintenance of electrical connections can prevent issues related to corrosion and wear over time.

Closing Paragraph

The P0672 trouble code signifies an important issue within your vehicle’s diesel engine system that requires prompt attention. By understanding its implications and following a systematic diagnostic approach, vehicle owners can effectively address this code. Whether you choose to tackle repairs yourself or consult with a professional mechanic, being informed about potential causes and solutions will aid in restoring your engine’s performance and reliability.

Frequently Asked Questions About P0672

• What does P0672 mean?
  It indicates a malfunction in the glow plug circuit for cylinder 2 in diesel engines.
• Can I drive my vehicle with a P0672 code?
  While it may still run, driving can lead to performance issues and increased wear on engine components.
• How do I know if my glow plug is bad?
  A multimeter test showing resistance outside 0.5 to 2.0 ohms typically indicates a faulty glow plug.
• Is replacing a glow plug expensive?
  The cost varies but generally ranges from $50 to $150 per glow plug plus labor if done by a mechanic.
• What tools do I need for diagnosing P0672?
  A digital volt-ohmmeter (DVOM) and an OBD-II scanner are essential for diagnosing this trouble code.
• When should I seek professional help?
  If you are unsure about performing electrical diagnostics or repairs, it’s best to consult with a qualified mechanic.
• Does this code affect all vehicles?
  P0672 primarily affects diesel vehicles equipped with glow plugs; gasoline engines do not use this system.
• How often should I check my glow plugs?
  Regular inspections during routine maintenance can help catch issues early; consider checking every 60,000 miles.