P0672 indicates the engine computer has detected an open electrical circuit in the glow plug system for cylinder 2. This prevents the glow plug from heating the combustion chamber, which is necessary for reliable cold starts in diesel engines. The issue is typically localized to the plug, wiring, or connector rather than the control module.
This is the most common cause as glow plugs wear out over time and eventually stop conducting electricity.
High heat and engine vibration can crack insulation or break wires leading to the glow plug.
Exposure to moisture and road salt can cause corrosion at the plug terminal, creating an open circuit.
The module supplying power to the plugs may fail internally, though this often affects multiple cylinders.
A short circuit elsewhere in the system may blow the main fuse supplying the glow plug bank.
Internal computer failure is extremely rare and should only be considered after all external components are verified.
No, this code almost always indicates a failed glow plug or wiring issue, not a computer failure.
Yes, but cold starting will be difficult and emissions may increase until repaired.
While only cylinder 2 is flagged, others may be near failure; replacing the set ensures uniform performance.
Some shops replace computers prematurely for electrical codes, but for glow plug circuits, the plug itself is the primary failure point.