P0673 Cylinder 3 Glow Plug Circuit

P0673 indicates a cylinder 3 glow plug circuit fault. The glow plug circuit for cylinder 3 is open, shorted, or drawing abnormal current.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not remove a glow plug unnecessarily before external resistance, voltage, and current checks are complete.

Symptoms of P0673

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0673

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Measure cylinder 3 glow plug resistance, commanded voltage, current draw, battery voltage, coolant temperature, and freeze-frame starting conditions.
Inspect cylinder 3 glow plug wiring, connector terminals, module output pin, harness heat damage, corrosion, and short-to-ground or open faults.
Compare cylinder 3 readings with other cylinders and repeat the test during a commanded glow cycle.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.