DTC P0670: Glow Plug Control Module Circuit Malfunction

Introduction

DTC P0670 is a common error that indicates a problem with the glow plug control module circuit. This code is mostly seen in diesel vehicles, where the glow plugs play a crucial role in starting a cold engine. A malfunction in this system can lead to difficult starting, increased emissions, and in some cases, damage to the engine itself. In this article, we will explore the symptoms, causes, diagnosis, and solutions for DTC P0670, providing practical help to auto mechanics.

Symptoms

When a fault occurs in the glow plug control module circuit, the following symptoms may occur:

  • Difficulty starting the engine, especially at low temperatures.
  • Emission of black or excessive smoke during ignition.
  • Engine Light (MIL) on dashboard comes on.
  • Irregular or insufficient heating of the glow plugs.
  • Possible vibrations or abnormal noises during engine operation.

Cause

The causes of the DTC code P0670 can be different and include:

  • Defective spark plugs :
    If one or more glow plugs are not working properly, the circuit may not operate as expected.

  • Wiring problems :
    Damaged wires, short circuits, or loose connections can cause the control module to malfunction.

  • Glow plug control module faulty :
    The module itself may be faulty, preventing proper signaling to the glow plugs.

  • Engine control unit (ECU) problems :
    A malfunctioning ECU may not correctly interpret data from the glow plug circuit.

  • Faulty sensors :
    Malfunctions in the engine temperature sensors can affect the operation of the glow plugs.

Diagnosis

Diagnosing DTC code P0670 requires a systematic approach:

  1. DTC Code Scan :
    Use an OBD-II diagnostic tool to check for DTC codes. It is also helpful to check for other related codes, such as P0671 (Glow Plug 1 Failure), P0672 (Glow Plug 2 Failure), and so on.

  2. Visual inspection :
    Check the glow plug control module wiring and connections for signs of damage or corrosion.

  3. Glow plug test :
    Measure the resistance of the glow plugs to identify any faults.

  4. Checking the control module :
    Check the glow plug control module for malfunctions using a multimeter.

  5. Engine Control Unit (ECU) Check :
    Make sure the ECU is working properly and that there are no other DTC codes that may affect the system.

Resolution and repair

Resolving DTC P0670 may require several procedures, depending on the cause identified:

  • Replacing the glow plugs :
    If one or more glow plugs are defective, replace them with OEM quality glow plugs.

  • Wiring Repair :
    If you encounter any wiring problems, repair or replace damaged wires and ensure secure connections.

  • Replacing the control module :
    If the glow plug control module is faulty, replace it with a known good unit.

  • Engine Control Unit (ECU) programming :
    If the ECU malfunctions, reprogramming or replacement may be necessary.

Insight: Components involved in the failure

When diagnosing and troubleshooting the DTC P0670 code, it is important to understand the key components involved in the glow plug ignition system:

  • Glow plugs :
    These electrical devices heat the air inside the combustion chamber to facilitate fuel ignition. Their efficiency is essential for easy starting.

  • Glow Plug Control Module :
    This module regulates the power supplied to the glow plugs based on engine temperature and other variables. A malfunction in this module can compromise the entire system.

  • Engine Control Unit (ECU) :
    The ECU controls the operation of the engine, including the ignition of the glow plugs. A problem with this component can also affect other aspects of engine operation.

Conclusions

DTC P0670 is a major indicator of problems in the glow plug circuit, and its diagnosis and resolution are essential to ensure optimal operation of the diesel engine. Through accurate diagnosis and a systematic approach, auto repairers can effectively identify and resolve problems associated with this code, improving customer satisfaction and vehicle life. Always remember to follow the manufacturer's guidelines and use reliable diagnostic tools to achieve accurate and long-lasting results.

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.