P0674 Cylinder 4 Glow Plug Circuit Fault

OBD2 Code: P0674

Description: Cylinder 4 Glow Plug Circuit Fault

Definition: This code indicates a malfunction in the glow plug circuit for cylinder number 4. The Engine Control Module (ECM) has detected an issue with the electrical circuit that controls the glow plug, which is responsible for heating the air in the combustion chamber to facilitate starting in diesel engines.

p0674 – Cylinder 4 Glow Plug Circuit Fault

Typical Severity: Moderate

Common Causes

P0674 – Cylinder 4 Glow Plug Circuit Fault

Common causes:

• Faulty glow plug in cylinder 4
• Wiring issues in the glow plug circuit of cylinder 4
• Loose or poor electrical connections related to the glow plug in cylinder 4
• Issues with the glow plug control module for cylinder 4

 

Common Misdiagnosis

OBD2 Code: P0674

Description: Cylinder 4 Glow Plug Circuit Fault

Common Misdiagnosis: Replacing the glow plug without checking the wiring or control module.

 

Common Diagnostic Steps

OBD2 Code: P0674

Description: Cylinder 4 Glow Plug Circuit Fault

• Check the glow plug for cylinder 4 for any visible damage or wear.
• Test the resistance of the glow plug using a multimeter to ensure it is within manufacturer specifications.
• Inspect the wiring and connectors leading to cylinder 4’s glow plug for corrosion, breaks, or loose connections.
• Verify that the power supply to the glow plug circuit is functioning correctly by checking fuses and relays associated with the system.
• If equipped, use an OBD2 scanner to clear the code and see if it returns after performing repairs or replacements.
• If issues persist, consider testing or replacing the glow plug control module as it may be faulty.