Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the part of the engine that helps it start when it's really cold isn't working right for cylinder number 4.
The engine control module (ECM) has detected a problem with the glow plug circuit in cylinder 4, indicating an open circuit or a malfunction.
P0674 indicates that the ECM has identified an issue with the glow plug circuit for cylinder 4. This could mean there's an open circuit, a faulty glow plug, or a problem with the wiring or connections leading to the glow plug. Glow plugs are used in diesel engines to help start the engine in cold conditions by heating the air in the cylinders.
• Difficulty starting the engine in cold weather
• Engine misfires
• Check Engine Light is on
• Faulty glow plug in cylinder 4
• Open or shorted wiring in the glow plug circuit
• Poor electrical connection at the glow plug
Glow Plug: A device used in diesel engines to heat the air in the cylinders to aid starting.
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the glow plug and wiring for damage.
• Test the glow plug for proper resistance.
• Replace the faulty glow plug.
• Repair or replace damaged wiring.
• Ensure all connections are secure and clean.
• OBD-II scanner
• Multimeter
• Socket set
$100 - $250
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Dodge Ram 2500
• Regularly inspect glow plugs and wiring.
• Use high-quality glow plugs.
• Ensure proper engine maintenance.
Sensor Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Consider replacing all glow plugs if one is faulty, especially in high-mileage vehicles.
Glow plug replacement may be covered under the vehicle's powertrain warranty. Check with the manufacturer.
Glow plug circuit issues are common in diesel engines, especially in older models or those with high mileage.
Moderate – While the vehicle may still run, starting issues in cold weather can be problematic.
Driving with a faulty glow plug can lead to increased emissions and potential engine damage.
• Engine is cold
• Ambient temperature is low
The glow plug for cylinder 4 is located on the engine block, typically near the top of the cylinder head.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to difficulty starting the engine in cold weather and potential engine damage over time.
Q: Can I drive with a P0674 code?
A: Yes, but it is not recommended as it can lead to starting issues and increased emissions.
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Universal · Digital multimeter
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.