OBD-II · Engine and powertrain (P)
P0670
Glow plug control module circuit fault
What it means
The diesel glow plug control module or the engine computer's command circuit to it is faulty.
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 |
| 02 | power feed or fuse fault |
| 03 | bad ground |
| 04 | wiring damage |
| 05 | shorted glow plug overloading the module |
What to check, step by step
- 01Check the module's main fuse, power feed and ground.
- 02With the circuit isolated, measure glow-plug resistance against the specification, compensating for meter-lead resistance, or compare current draw. Very low resistance alone is normal for many glow plugs and does not prove a short.
- 03Inspect the command and feedback wiring to the engine computer.
- 04Replace the module, and any shorted glow plug, if confirmed faulty.