P0670
ModerateP0670 — Glow Plug Control Module Malfunction
Description
What P0670 Means
Code P0670 points to a fault in the glow plug control module itself. On BMW diesel engines, this module supplies power to the glow plugs on command from the engine control unit (DME).
On some BMW diesels, a failed controller may not set a dedicated code and instead shows up as faults on all glow plugs at once. When the module itself fails, the dedicated code P0670 can appear.
The glow plug system includes the glow plugs, the control module, and the wiring. The module takes commands from the DME and controls glow plug heating to ease cold starts and reduce exhaust emissions.
Symptoms
Symptoms
- Hard cold starts.
- Multiple glow plug fault codes.
- Check Engine Light (CEL) on the instrument cluster.
Causes and fixes
Diagnosis and Repair
- Scan the glow plug control module: Check the module with diagnostic equipment (ISTA, INPA).
- Check power and ground: Confirm the module has power and a solid ground.
- Check output signals: Test the module's output signals to the glow plugs.
- Replace the module: If the fault is confirmed, replace the glow plug control module.