OBD-II · Engine and powertrain (P)
P0674
Glow plug circuit cylinder 4 open
What it means
The glow plug control sees an open or faulty circuit on cylinder 4's glow plug - most often the glow plug itself has burnt out.
Symptoms
- harder starting when cold
- rough running and white smoke for the first moments after a cold start
- glow plug light may flash
- possibly no symptoms in warm weather
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | burnt-out glow plug in cylinder 4 |
| 02 | loose, corroded or disconnected plug connector |
| 03 | damaged wire between module and plug |
| 04 | glow plug control module output fault |
What to check, step by step
- 01Unplug the glow plug and measure its resistance: open circuit means it has failed; compare with the other cylinders.
- 02Check the connector and wire from the module to the plug.
- 03Check the module output with a test light or current clamp during pre-heat.
- 04When replacing glow plugs, work on a warm engine with the correct torque; if one feels seized, stop - a snapped glow plug means removing the cylinder head or drilling it out.
- 05On high-mileage engines consider replacing all plugs together.