OBD-II · Engine and powertrain (P)
P0683
Glow plug control module to engine computer communication
What it means
The feedback or data link between the glow plug control module and the engine computer has a fault, so the computer cannot confirm glow plug status.
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 | failed glow plug control module (often after a glow plug shorted) |
| 02 | wiring open or short on the feedback line |
| 03 | corroded connector at the module |
| 04 | module power or ground fault |
What to check, step by step
- 01Check module power, ground and fuse.
- 02Inspect the module connector for corrosion.
- 03Check the feedback wire between module and engine computer.
- 04Check glow plugs for shorts before fitting a new module.