P0672 - Cylinder no. glow plug circuit 2 (Glow Plug Circuit Cylinder No. 2)

Introduction

DTC P0672 is a diagnostic code indicating a problem with the cylinder 2 glow plug circuit. This code is especially relevant for diesel vehicles, where glow plugs are critical to heating the combustion chamber and ensuring proper ignition of the fuel. A failed glow plug can lead to difficult starting, increased smoke emissions, and overall reduced engine performance.

Symptoms

The presence of the DTC code P0672 can manifest itself through various symptoms, including:

  • Difficulty starting the engine, especially in cold conditions.
  • Black or blue smoke from the exhaust when starting or accelerating.
  • Increased engine noise during operation.
  • Warning light on the dashboard (check engine).
  • Engine performance impaired, possibly resulting in loss of power.

Cause

The causes of the DTC code P0672 can be different, and include:

  • Cylinder 2 glow plug failure.
  • Short circuit or open circuit in the glow plug wiring.
  • Glow plug relay malfunction.
  • Problems with the engine control unit (ECU) that manages the glow plug circuit.
  • Oxidized or faulty contacts between the glow plug terminals and the wiring.

Diagnosis

Diagnosing the P0672 code requires a systematic approach. Here are the recommended steps:

  1. DTC Code Scan :
    Start by scanning the engine control unit for related DTC codes, such as P0671 (cylinder 1 glow plug circuit) or P0673 (cylinder 3 glow plug circuit).

  2. Visual inspection :
    Visually inspect the wiring and connectors associated with the 2 cylinder glow plug for any signs of wear, burning, or oxidation.

  3. Glow plug test :
    Use a multimeter to test the resistance of the glow plug. A resistance value that is too high or too low can indicate a fault.

  4. Relay Check :
    Make sure the glow plug relay is working properly by testing or replacing if necessary.

  5. ECU Check :
    If the above steps reveal no problems, your engine control unit may need to be updated or replaced.

Resolution and repair

Once the cause of the problem has been identified, you can proceed with the resolution. Corrective actions may include:

  • Replacing the spark plug :
    If the glow plug is faulty, replace it with a new quality one, making sure it is compatible with the vehicle model.

  • Wiring Repair :
    If there are any problems with the wiring, make the necessary repairs, making sure to use high-quality materials to ensure the longevity of the repair.

  • Replacing the relay :
    If the glow plug relay is not working, replace it to restore proper power to the glow plug.

  • Checking the control unit :
    If there are problems with the ECU, a firmware update may be necessary or, in more serious cases, the replacement of the control unit itself.

Insight: Components involved in the failure

When dealing with the DTC code P0672, it is helpful to know the specific components involved in the glow plug circuit, which include:

  • Spark plug :
    This component is a heating element that activates to preheat the combustion chamber, facilitating fuel ignition.

  • Glow plug relay :
    It acts as a switch that controls the electrical power to the glow plug. A malfunctioning relay can prevent the glow plug from firing.

  • Wiring :
    The wires that connect the glow plug to the engine control unit and relay. Damage to these wires can cause breaks in the circuit.

  • Engine Control Unit (ECU) :
    Manages the operation of the glow plugs and communicates with other engine systems to optimize performance and efficiency.

Conclusions

The DTC P0672 trouble code is a significant problem for diesel vehicles, requiring attention and accurate diagnosis. Recognizing the symptoms and understanding the potential causes is key to effective resolution. Through thorough diagnosis and maintenance of the affected components, optimal engine functionality can be restored and reliable performance can be maintained over time. Mechanics and auto repairers should always consider replacing glow plugs and relays as a key part of preventative maintenance for diesel vehicles.

Important
Not all OBD2 codes used by one manufacturer are used by other brands, and may not have the same meaning.
The information presented here is for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any concerns about repairing your vehicle, please contact your repair shop.