P0674 GMC Code - Cylinder 4 Glow Plug Circuit Fault
Quick Answer
The P0674 diagnostic trouble code (DTC) for GMC vehicles specifically refers to a fault in the glow plug circuit of cylinder 4. Common causes include Faulty glow plug in cylinder 4, Damaged wiring harness connecting the glow plug, Malfunctioning glow plug relay. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0674 GMC indicates Cylinder 4 Glow Plug Circuit Fault.
- Common causes
- Common causes include Faulty glow plug in cylinder 4, Damaged wiring harness connecting the glow plug, Malfunctioning glow plug relay.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0674 GMC Description
The P0674 diagnostic trouble code (DTC) for GMC vehicles specifically refers to a fault in the glow plug circuit of cylinder 4. Glow plugs are essential components in diesel engines, as they heat up the combustion chamber to facilitate cold starts. When the engine is cold, the glow plugs help ignite the fuel-air mixture by providing additional heat. In the case of cylinder 4, a fault in the glow plug circuit can lead to difficulties starting the engine, reduced engine performance, increased emissions, and potential damage to the engine over time.
Common Causes of P0674 GMC
- Faulty glow plug in cylinder 4.
- Damaged wiring harness connecting the glow plug.
- Malfunctioning glow plug relay.
- Defective engine control module (ECM).
- Corrosion or poor connections in the glow plug circuit.
Symptoms of P0674 GMC
- Difficulty starting the engine, especially in cold weather.
- Rough idling or engine misfires.
- Reduced engine performance and acceleration.
- Increased exhaust smoke.
- Engine stalling or hesitation during acceleration.
How to Fix P0674 GMC
- Diagnose the specific cause of the glow plug circuit fault using a scan tool.
- Inspect the glow plug in cylinder 4 and test its functionality.
- Check the wiring harness for any damage or corrosion and repair or replace as needed.
- Test the glow plug relay and replace if faulty.
- Verify the ECM's operation and reprogram or replace if necessary.
Cost to Fix P0674 GMC
The typical repair costs for addressing a cylinder 4 glow plug circuit fault can range from $150 to $400, including parts and labor. However, the actual cost may vary depending on the specific cause of the issue, the vehicle's make and model, and the labor rates at the auto repair shop. It is advisable to consult with a professional mechanic to get an accurate estimate based on the individual circumstances. Keep in mind that diagnostic time and labor rates can vary, so it's essential to inquire about these details before proceeding with the repair.
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Information for Specific GMC Models
- P0674 2014 GMC Sierra — Cylinder 4 Glow Plug Circuit Fault
- P0674 2015 GMC Sierra — Cylinder 4 Glow Plug Circuit Fault
- P0674 2016 GMC Sierra — Cylinder 4 Glow Plug Circuit Fault
- P0674 2017 GMC Sierra — Cylinder 4 Glow Plug Circuit Fault
- P0674 2018 GMC Sierra — Cylinder 4 Glow Plug Circuit Fault
Frequently Asked Questions about P0674 GMC Code
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