OBD-II · Engine and powertrain (P)
P0380
Glow plug/heater circuit A fault
What it means
The diesel glow plug (pre-heat) circuit A has a fault. Glow plugs heat the combustion chambers for cold starts and often keep working after start to reduce smoke.
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 | one or more failed glow plugs |
| 02 | glow plug relay or control module fault |
| 03 | blown fuse |
| 04 | wiring or connector damage |
| 05 | engine computer control fault |
What to check, step by step
- 01Check for cylinder-specific glow plug codes (P0671-P0676) - they narrow it down.
- 02Measure each glow plug's resistance or current draw; compare cylinders.
- 03Check the fuse, relay/control module supply and ground.
- 04Inspect the glow plug wiring and connectors.
- 05When 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.