P0384
Glow Plug Control Module 1 Control Circuit High
Glow plug / diesel starting
Generic OBD-II
High
What it means
P0384 means the ECM detected an abnormally high voltage on the control circuit for glow plug control module 1. Glow plugs preheat a diesel's combustion chambers for starting, so a fault here — from wiring shorted to voltage, a bad connector, or a failed module — mainly causes hard cold starting, rough cold running, and white exhaust smoke.
High
Can I keep driving? Runs normally once warm; the main effect is hard cold starting, rough cold running, and possible white smoke until the glow plug system is fixed.
Common symptoms
What you'll notice
- Check-engine light (and often the glow-plug/wait-to-start light) on
- Hard starting, especially in cold weather
- Rough running and white smoke on a cold start
- Reduced performance while the engine is cold
Common causes
Most likely first
- Faulty glow plug control moduleLikely
- Wiring shorted to voltage (high) in the control circuitCommon
- Loose or corroded connector at the moduleCommon
- One or more failed glow plugsLess often
- Failed ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for companion glow-plug codes.
- Inspect the glow plug control module connector and wiring for a short to voltage or corrosion.
- Measure the control circuit voltage and compare to spec.
- Test the individual glow plugs for correct resistance and replace any that are open.
- Replace the glow plug control module if the circuit stays high. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0384?+
Yes once the engine is running and warm. The real problem is cold starting — plan to fix it before cold weather, since a diesel can become very hard to start without working glow plugs.
Can I just clear P0384?+
It returns while the circuit still reads high. Repair the module or wiring first, then clear and re-test.
Related codes
Often seen with P0384
Read & clear P0384 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX