What is the fault code P0674? What is the Cylinder 4 Glow plug Circuit / Open Malfunction description? How do I fix the P0674 fault code What are the symptoms and causes for the P0674 fault code
What is the P0674 Fault code? What does it signify?
A P0674 code is a way to indicate that you are a professional. “Cylinder4 Glow Plug Circuit/Open . This code is generated when the powertrain controller module (PCM), detects a fault in the cylinder 4 glowplug circuit.
When the engine is cold, compressed air temperature quickly loses its heat. This problem is solved by a preheating device called a glow-plug. One glow plug is typically per cylinder. These are installed directly through the cylinder head, as close as possible to the combustion chamber.
Glow plugs can be controlled by the powertrain controller module (PCM), which monitors coolant oil, transmission, and intake air temperatures. If the PCM senses cold engine, the PCM will activate the glow plug to help with starting. Code P0674 will trigger if the PCM senses that the glowplug is not getting hot. This code usually indicates a fault in the electrical circuit and points at the glow plug of the cylinder #4.
When the engine is hot, however, glow plugs will not be required. To prevent damage to the engine and glow plugs, the PCM switches off the glow control system once the coolant temperature has reached a certain threshold.
What causes the P0674 Fault code?
The following are the most frequent causes of the P0674 error code:
- – Defective glowing plug (Cylinder 4-)
- – A defective timer or control module for glow plug control
- – Defective, corroded, or damaged wires, harnesses, and any associated connectors in the glow bulb circuit
- – Defective glowplug relay
- – Blown fuse
What are the P0674 Malfunction Code Symptoms
You may experience the following symptoms if your vehicle has the code P0674:
- – Illumination and control of the check engine light
- – Too long waiting to start the engine
- In cold weather, the engine might not start at all
- – The Preheat light doesn’t turn on or stay on constantly
- – The vehicle’s exhaust emits white smoke when it is being started
- – The engine may lose power while it warms up.
- – Extremely loud engine noise
- Engine misfire
How to Fix the P0674 Fault Code
Diagnose this code first if you find a P0670(Glow Plug Control Module Circuit Malfunction code) along with the code.
There are several repairs that can resolve the P0674 fault code.
- – Repair or replacement damaged, corroded, fused and loose wires
- Repair or replacement bent or damaged pins in electric connectors
- – Repairing open or short circuit issues and replacing blown fuses
- – Replacing the defective glow bulb in cylinder 4.
- Relay for a defective glow plug
- – Replacing a faulty timer or glow plug control module
- Clear all codes and test the vehicle. Recheck the PCM to verify that no codes have been reset.
How Serious Is the P0674 Fault Code
A code P0674 does not usually prevent a vehicle’s starting. The engine can still run if only one spark plug has failed. The engine will start more difficult in colder weather, as the temperature changes and time passes. This can result in a loss of power or acceleration.
