P0671: Glow Plug Cylinder No. 1 Circuit Code

Introduction

The DTC P0671 trouble code indicates a problem with the glow plug circuit for cylinder 1 in a diesel engine. The glow plug, or glow plug, is a crucial component in ensuring an efficient engine start, especially in cold weather. In this article, we will explore the symptoms, causes, diagnosis, troubleshooting, and repair of this problem, providing a useful reference for auto mechanics.

Symptoms

The P0671 code can manifest itself with several symptoms that can vary depending on the vehicle and the severity of the problem. Here are some common symptoms that may indicate a malfunctioning glow plug in cylinder 1:

  • Difficulty starting the engine, especially in cold conditions
  • Thick, dark exhaust fumes when starting
  • Engine idles or runs rough
  • "Check Engine" light on dashboard
  • Increased fuel consumption

Cause

The causes of the P0671 error code can be many. Some of the most common reasons include:

  • Faulty spark plug :
    The glow plug in cylinder 1 may be burned out or bad.

  • Wiring problems :
    The wires or connectors connecting the glow plug to the ECU may be damaged or corrupted.

  • Engine control unit malfunction :
    The ECU may not provide the correct signal to activate the glow plug.

  • Power problems :
    Inadequate electrical supply to the glow plug can cause malfunctions.

  • Mass problems :
    A bad ground connection can affect the operation of the glow plug.

Diagnosis

Diagnosing the P0671 code requires a systematic approach. Here are the recommended steps:

  1. Vehicle Scan :
    Use a DTC reader to confirm the presence of the P0671 code and check for any related codes (e.g. P0672 for cylinder 2 glow plug).

  2. Visual inspection :
    Visually inspect the wiring and connectors associated with the No. 1 cylinder glow plug for signs of wear, corrosion, or damage.

  3. Glow plug test :
    Use a multimeter to test the resistance of the glow plug. A resistance value out of specification indicates that the glow plug needs to be replaced.

  4. Checking the voltage :
    Check that there is voltage input to the glow plug during the preheating process. A missing or incorrect voltage reading suggests a problem with the power supply or the engine control unit.

  5. Engine control unit check :
    Perform a thorough diagnostic on the ECU to ensure there are no internal malfunctions.

Resolution and repair

Once you have diagnosed the problem, you can proceed to troubleshooting. Here are some common solutions:

  • Replacing the spark plug :
    If the glow plug is defective, it must be replaced with a new one. Make sure to use quality replacement parts.

  • Wiring Repair :
    If any damage is found to the cables or connectors, proceed to repair or replace them.

  • Power supply control :
    If there are power problems, check the electrical circuit and resolve any interruptions.

  • Resetting codes :
    Once repairs are complete, it is important to clear the DTC codes from the engine control unit and test drive the vehicle to ensure the problem is resolved.

Insight: Mechanical and Electrical Components Involved

When diagnosing and repairing DTC code P0671, it is helpful to better understand the components involved:

  • Spark plug :
    The glow plug is a heating element that is activated before the engine starts to preheat the cylinder. An efficient glow plug is essential to ensure rapid ignition and reduce emissions.

  • ECU :
    The engine control unit controls the ignition of the glow plug and monitors the engine operation. If the ECU is not working properly, it may send incorrect signals or not activate the glow plug.

  • Wiring :
    The wires that connect the glow plug to the ECU are crucial to the proper functioning of the system. Damaged or dirty wiring can interrupt the flow of current and cause malfunctions.

  • Mass :
    Grounding is essential to the electrical stability of the system. Improper grounding can adversely affect the operation of the glow plug.

Conclusions

DTC P0671 is a serious problem that can affect the reliability and performance of your diesel engine. Through accurate diagnosis and proper resolution, auto repairers can effectively address this code and keep your vehicle running at its best. Always remember to perform regular checks and maintenance to prevent future problems.

A thorough understanding of the components involved and the diagnostic and repair procedures can make the difference between a quick and effective diagnosis and a long and costly series of trial and error. Make sure you stay up to date with the latest technologies and repair practices in the mechatronics industry to always provide the best possible service to your customers.

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.