P0674 Cylinder 4 Glow Plug Circuit

OBD2 Code: P0674

Description: Cylinder 4 Glow Plug Circuit

Definition: This code indicates that there is an issue with the glow plug circuit in cylinder number 4. The Engine Control Module (ECM) has detected a fault in the electrical circuit of the glow plug for this specific cylinder, which may affect engine starting and performance, especially in cold conditions.

p0674 – Cylinder 4 Glow Plug Circuit

Severity: Moderate

Common Causes

p0674 – Cylinder 4 Glow Plug Circuit

Description: The PCM has detected a problem in the cylinder 4 glow plug circuit, indicating an issue with the glow plug or its circuit.

Common Causes:

• Faulty glow plug in cylinder 4
• Wiring issues in the glow plug circuit for cylinder 4
• Loose or corroded connections in the glow plug circuit
• Defective glow plug relay

Common Misdiagnosis

OBD2 Code: P0674

Description: Cylinder 4 Glow Plug Circuit

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

• Check the glow plug for cylinder 4 for continuity and resistance.
• Inspect the wiring harness and connectors for damage or corrosion.
• Test the glow plug relay and control module for proper operation.
• Verify battery voltage is reaching the glow plug circuit.
• Replace any faulty components as necessary, such as the glow plug or relay.
• Clear the code and test drive to ensure it does not return.