Description of the P0672 fault code.
OBD2 Error Codes

P0672 Cylinder 2 Glow Plug Circuit Malfunction

26.05.2022 /

P0672 – OBD-II Trouble Code Technical Description

Trouble code P0672 is a generic trouble code that indicates a fault in the cylinder 2 glow plug circuit.

What does the fault code mean P0672?

Trouble code P0672 indicates a problem with the glow plug circuit in cylinder No. 2. The glow plug is used in diesel engines to warm the cylinders before starting and during operation. If the P0672 code appears, it means that the engine control module (PCM) has detected that the voltage in the No. 2 cylinder glow plug circuit is not within the manufacturer's specified voltage range.

Fault code P0672.

Possible reasons

Possible reasons for DTC P0672 may include the following:

  • Defective glow plug: The glow plug itself in cylinder No. 2 may be damaged or failed, resulting in improper heating or no heating at all before the engine starts.
  • Wiring and connections: The wiring connecting the glow plug to the engine control module (PCM) may be damaged, broken, or have poor contact, causing problems with electrical signal transmission.
  • Problems with the engine control module (PCM): A malfunction in the engine control module can cause the glow plug data to be misinterpreted and cause P0672 to appear.
  • Circuit voltage problems: The voltage supplied to the glow plug may be insufficient due to problems with the vehicle's electrical system, such as a dead battery, damaged voltage regulator, or problems with the alternator.
  • Problems with other heating system components: Faults in other heating system components, such as the air preheater or heating controller, can also cause P0672 to appear.

To accurately determine the cause of error P0672, it is recommended to diagnose the vehicle using specialized tools and equipment.

What are the symptoms of a fault code? P0672?

If DTC P0672 is present, you may experience the following symptoms:

  • Difficulty starting the engine: A malfunction in the No. 2 cylinder glow plug may make the engine difficult to start, especially in low temperatures or after an extended period of inactivity.
  • Increased smoke level: A malfunctioning glow plug may cause incomplete combustion of the fuel in the cylinder, which may result in increased smoke emission from the tailpipe.
  • Rough engine operation: Uneven engine operation or vibration may occur if the No. 2 cylinder is not sufficiently heated before starting.
  • Increased fuel consumption: Improper operation of the glow plug may result in inefficient fuel combustion, which may increase fuel consumption.
  • Performance degradation: Insufficient heating of the No. 2 cylinder can reduce engine performance, especially during the early stages of operation after starting.
  • Emergency engine operation mode (limp mode): In some cases, the vehicle may enter limp mode to prevent possible damage to engine management system components.

These symptoms may occur to varying degrees depending on the specific problem and the condition of the vehicle.

How to diagnose a fault code P0672?

The following steps are recommended to diagnose DTC P0672:

  1. Scanning error codes: Use a diagnostic scanner to read all trouble codes, including P0672. This will help determine if there are other problems that may be related to the glow plug failure.
  2. Visual inspection of the glow plug: Check the glow plug in cylinder No. 2 for visible damage, corrosion or signs of oxidation. Pay attention to the color of the insulator and electrodes, which may indicate the condition of the spark plug.
  3. Checking wiring and connections: Inspect the wiring connecting the glow plug to the engine control module (PCM) for damage, breaks, or oxidized contacts. Make sure all connections are secure.
  4. Glow plug resistance testing: Use a multimeter to check the glow plug resistance. The resistance must be within the manufacturer's specifications. Deviations from the norm may indicate a faulty spark plug.
  5. Engine Control Module (PCM) Diagnostics: Test the PCM to identify any malfunctions or errors in its operation that may be related to the P0672 code.
  6. Additional tests: If necessary, additional tests may be required, such as checking the voltage in the glow plug circuit, analyzing the operation of other components of the ignition system and fuel system.

After diagnosing and identifying the cause of the P0672 error, it is necessary to take appropriate measures to repair or replace the faulty components. If you are unsure or lack experience, it is recommended that you contact a qualified auto mechanic or service center.

Diagnostic errors

When diagnosing DTC P0672, the following errors may occur:

  1. Skipping a visual inspection: Failure to visually inspect the glow plug or wiring may result in obvious problems such as damage, corrosion or breaks being missed.
  2. Incorrect interpretation of test results: Misinterpretation of glow plug resistance or circuit voltage test results may lead to incorrect conclusion about the condition of the component.
  3. Skipping diagnostics for other components: Ruling out other possible causes, such as problems with the wiring, connections, engine control module (PCM), or other ignition system components, may lead to an incorrect diagnosis.
  4. Incorrect component replacement: Replacing the glow plug without first diagnosing it or considering other possible causes of the P0672 code may not be effective.
  5. Skipping a software update: Some problems with the P0672 code may be due to software errors in the engine control module. Skipping a PCM software update may cause the problem to continue.
  6. Incorrect error code removal: You must ensure that after repairing or replacing the faulty components, the error code has been successfully cleared from the PCM memory and all required adaptive reset procedures have been completed.

To avoid these errors, it is important to conduct a comprehensive diagnosis, taking into account all possible causes and carefully checking all components associated with the P0672 code.

How serious is the fault code? P0672?

The severity of the P0672 trouble code depends on several factors, including what causes it, engine type, and vehicle operating conditions. In general, the P0672 code should be considered serious as it indicates a problem with the glow plug in a specific cylinder, several aspects to consider:

  • Difficulty starting the engine: If the glow plug is not functioning correctly, it may cause difficulty starting the engine, especially during cold periods or when the vehicle has been parked for extended periods of time.
  • Engine damage: A malfunctioning glow plug can cause fuel to burn improperly in the cylinder, which can cause damage to the engine or other system components.
  • Potential problems with fuel economy and performance: Improper glow plug operation can result in inefficient fuel combustion, which can increase fuel consumption and reduce engine performance.
  • Possible entry into limp mode: In some cases, the vehicle may go into limp mode to prevent possible damage or failure due to a faulty glow plug.
  • Unpredictable consequences: A faulty glow plug can have unpredictable effects on engine performance, which may cause other problems such as increased wear or failure of other components.

So, trouble code P0672 should be taken seriously and should be corrected as soon as possible to avoid further problems with the vehicle and ensure its safe and efficient operation.

What repair will help eliminate the code? P0672?

To resolve DTC P0672, you must take the following steps, depending on the cause of the problem:

  1. Replacing the glow plug: If the cause of the error is a malfunction of the glow plug itself, then it must be replaced with a new one. It is recommended to use high-quality original spare parts or analogues from reliable manufacturers.
  2. Checking and restoring wiring: Check the wiring connecting the glow plug to the engine control module (PCM). If damage, corrosion or broken wiring is detected, it must be restored or replaced.
  3. Engine Control Module (PCM) Diagnostics: If there are possible malfunctions in the engine control module, it may require diagnostics and, if necessary, replacement or repair.
  4. Checking and Correcting Electrical System Problems: Check the condition of the battery, voltage regulator, alternator and other electrical system components that may affect glow plug performance.
  5. Updating the software: If necessary, update the engine control module software to the latest version to resolve possible software problems.
  6. Additional events: Depending on the specific situation, additional measures may be required, such as checking the operation of other components of the ignition system or fuel system.

It is important to note that accurately identifying and eliminating the cause of the P0672 code may require additional diagnostics and professional skills. Therefore, if you do not have experience in car repairs, it is recommended that you contact a qualified auto mechanic or service center.

How to Fix P0672 Engine Code in 3 Minutes [2 DIY Methods / Only $9.57]

P0672 – Brand-specific information

List of several popular car brands with decoding of trouble code P0672:

This is just a small list of examples, and the meaning of the P0672 code may vary slightly depending on the specific model and year of the vehicle. For more accurate information, it is recommended that you consult the service documentation, service manuals, or qualified technicians for your specific vehicle make and model.

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