AutoCodes – Chevrolet – P0674 Chevrolet

P0674 Chevrolet Code - Cylinder 4 Glow Plug Circuit Fault

Quick Answer

n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #4 glow plug, Cylinder #4 glow plug harness is open or shorted, Cylinder #4 glow plug circuit poor electrical connection. 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 Chevrolet indicates Cylinder 4 Glow Plug Circuit Fault.
Common causes: Common causes include Faulty cylinder #4 glow plug, Cylinder #4 glow plug harness is open or shorted, Cylinder #4 glow plug circuit poor electrical connection.
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 Popularity 2,430

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 24, 2024

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P0674 Chevrolet Description

n the diesel engine, air alone is compressed in the cylinder. Then, after the air has been compressed, a charge of fuel is sprayed into the cylinder and ignition occurs, due to the heat of compression. Eight glow plugs are used as an aid to starting.
Control of the glow plugs is accomplished by the Glow Plug Control Module. The nominal voltage for the glow plugs is 5.4 volts. When the ignition is turned On, the Glow Plug Control Module applies 7.2 V for 2.2 s, then 5.7 V for 0.8 s, and then 5.4 V until 1200°C (2192°F) is reached. The maximum voltage of the system is 10 V. While the engine is running the voltage will vary between 4.7 - 10 V when in closed loop control to maintain a glow plug temperature that ranges from 1150° - 1180°C (2102° - 2156°F). The temperature and the power consumption are controlled between the Engine Control Module (ECM) and the Glow Plug Control Module within a wide range to suit the engine's pre-heating requirements. Each glow plug is energized individually. This capability yields more optimum heat times for the glow plugs, thus pre - glow times can be kept to a minimum for a short wait to crank times and maximum glow plug durability.

OBDII Code P0674 Chevrolet - Cylinder 4 Glow Plug Circuit Fault - AutoCodes.com — P0674 Chevrolet Code - Cylinder 4 Glow Plug Circuit Fault

What does this mean?

What are the Possible Causes of the DTC P0674 Chevrolet?

Faulty cylinder #4 glow plug
Cylinder #4 glow plug harness is open or shorted
Cylinder #4 glow plug circuit poor electrical connection
Faulty Glow Plug Control Module (GPCM)

How to Fix the DTC P0674 Chevrolet?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0674 Chevrolet code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Need more information on how to fix the P0674 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0674 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P0674 2014 Chevrolet Silverado — Cylinder 4 Glow Plug Circuit Fault
P0674 2015 Chevrolet Silverado — Cylinder 4 Glow Plug Circuit Fault
P0674 2016 Chevrolet Silverado — Cylinder 4 Glow Plug Circuit Fault
P0674 2017 Chevrolet Silverado — Cylinder 4 Glow Plug Circuit Fault
P0674 2018 Chevrolet Silverado — Cylinder 4 Glow Plug Circuit Fault

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0674 Chevrolet Code

1. What are the common symptoms of OBDII code P0674 in a Chevrolet, indicating a Cylinder 4 Glow Plug Circuit Fault?

The common symptoms include hard starting, rough idle, misfiring, decreased fuel efficiency, and the illumination of the Check Engine Light.

2. What are the possible causes of the Cylinder 4 Glow Plug Circuit Fault in a Chevrolet triggering code P0674?

Potential causes may include a faulty glow plug in cylinder 4, damaged wiring or connectors in the glow plug circuit, a defective glow plug control module, or issues with the engine control module (ECM).

3. How can I diagnose the Cylinder 4 Glow Plug Circuit Fault triggering OBDII code P0674 in my Chevrolet?

Diagnosis typically involves inspecting the glow plug in cylinder 4, checking the wiring and connectors in the glow plug circuit for damage, testing the glow plug control module, and using a scan tool to retrieve and interpret the fault codes.

4. Is it safe to continue driving my Chevrolet with OBDII code P0674 related to a Cylinder 4 Glow Plug Circuit Fault?

It is not recommended to drive the vehicle extensively with this code present, as it can lead to engine performance issues and potential damage over time. It is best to address the underlying problem promptly.

5. How can I repair the Cylinder 4 Glow Plug Circuit Fault causing OBDII code P0674 in my Chevrolet?

Repair options may include replacing the faulty glow plug in cylinder 4, repairing or replacing damaged wiring or connectors, checking and potentially replacing the glow plug control module, or addressing any ECM issues as needed.

6. Can a DIY enthusiast fix the Cylinder 4 Glow Plug Circuit Fault triggering OBDII code P0674 in a Chevrolet?

Depending on your skill level and access to tools, some DIY enthusiasts may be able to address this issue themselves by following repair guides and consulting service manuals. However, seeking professional help is recommended if unsure.

7. Will resetting the Check Engine Light resolve the OBDII code P0674 related to a Cylinder 4 Glow Plug Circuit Fault in my Chevrolet?

Simply resetting the Check Engine Light without addressing the underlying issue will not fix the problem. It is essential to diagnose and repair the root cause of the fault code to prevent it from reoccurring.

8. Are there any preventive maintenance tips to avoid encountering the Cylinder 4 Glow Plug Circuit Fault leading to OBDII code P0674 in a Chevrolet?

Regularly inspecting and maintaining the glow plug system, checking for loose or damaged wiring, and following the manufacturer's recommended service intervals can help prevent such faults from occurring.

9. Can extreme weather conditions impact the likelihood of experiencing the Cylinder 4 Glow Plug Circuit Fault causing OBDII code P0674 in a Chevrolet?

Yes, extreme cold temperatures can put additional strain on the glow plug system, potentially leading to failures or malfunctions. Ensuring the glow plug system is in good condition is crucial, especially in cold climates.

10. How long does it typically take to repair the Cylinder 4 Glow Plug Circuit Fault associated with OBDII code P0674 in a Chevrolet?

The repair time can vary depending on the exact cause of the fault, the extent of the repairs needed, and the experience of the technician. In general, it may take a few hours to a full day to diagnose and fix the issue.