Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the little heater in the engine that helps start the car when it's cold. It's like when your electric blanket doesn't work because there's a broken wire.
The P0677 code indicates that the engine control module (ECM) has detected an open circuit in the glow plug circuit for cylinder 7.
The glow plug is a heating device used to aid the starting of diesel engines. The ECM monitors the glow plug circuit and if it detects an open circuit or a fault in the wiring or the glow plug itself, it triggers the P0677 code.
• Engine hard to start in cold conditions
• Check Engine Light illuminated
• Rough idle when cold
• Faulty glow plug
• Open or shorted glow plug circuit wiring
• Faulty glow plug control module
Glow Plug: A device used to heat the combustion chambers of diesel engines to aid starting.
ECM: Engine Control Module, the computer that controls engine functions.
• Inspect the glow plug and its wiring for damage.
• Test the glow plug with a multimeter for continuity.
• Check the glow plug control module for faults.
• Replace the faulty glow plug.
• Repair or replace damaged wiring in the glow plug circuit.
• Replace the glow plug control module if necessary.
• Multimeter
• Socket set
• Screwdriver set
$100 - $300
Moderate
• Ford F-250
• Chevrolet Silverado
• Dodge Ram 2500
• Regularly check the glow plug system.
• Ensure wiring connections are secure.
• Replace glow plugs at recommended intervals.
Sensor Issue
• Have the glow plug system checked before winter.
• Avoid prolonged cranking of the engine in cold weather.
Glow plugs may be covered under the vehicle's powertrain warranty. Check with your manufacturer.
Glow plug issues have been common in diesel engines, especially in colder climates where starting is more challenging.
Moderate – It affects starting in cold weather, but the vehicle may still run once started.
Driving with a faulty glow plug can lead to increased emissions and potential engine damage.
• Engine should be cold.
• Battery should be fully charged.
The glow plug for cylinder 7 is typically located on the engine block near the seventh cylinder.
Q: Can I drive with a P0677 code?
A: Yes, but it may be difficult to start the vehicle in cold weather.
Q: How do I know if my glow plug is bad?
A: Symptoms include hard starting, rough idle, and a check engine light.
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