P0673Cylinder 3 Glow Plug Circuit
What it means
The glow plug control sees an electrical fault in the cylinder 3 glow plug circuit, usually an open plug. With the engine warm the car runs normally, so the code and a measurement are the only clues.
Symptoms
- Hard cold start
- White smoke and shaking for a few seconds after a cold start
- Glow plug warning light on some cars
Common causes
- Open glow plug on cylinder 3
- Broken or corroded glow plug wire or connector
- Glow plug control module fault
What to check first
- Measure the glow plug resistance (typically 0.5–1.5 Ω; OL means open)
- Check the supply from the control module during pre-glow
- If one plug failed, check the others: they are usually the same age
Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.