P0382
Glow Plug/Heater Circuit B
Glow plug / diesel starting
Generic OBD-II
High
What it means
P0382 is a diesel code meaning the engine computer has detected a fault in glow-plug (pre-heat) circuit 'B'. Glow plugs warm the combustion chambers so a cold diesel will start; a fault in this circuit mainly causes hard cold starts, rough warm-up, and white smoke rather than affecting the fully warmed engine.
High
Can I keep driving? Drivable once warm, but expect hard cold starts and rough running until warm-up — the fault is in the diesel glow-plug (pre-heat) circuit, not the running engine.
Common symptoms
What you'll notice
- Check-engine light on (or glow-plug/wait-to-start light)
- Hard starting, especially in cold weather
- Rough running and white smoke during cold start and warm-up
- Reduced performance until the engine warms up
Common causes
Most likely first
- Faulty glow plug on circuit 'B'Likely
- Open or shorted glow-plug circuit wiring or connectorCommon
- Faulty glow-plug control module or relayCommon
- Poor electrical connection or ground in the glow-plug circuitLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the glow-plug wiring, connectors, and relay for damage or corrosion.
- Measure each glow plug's resistance and replace any that are open or out of spec.
- Check the glow-plug control module output and supply voltage.
- Repair any open/short in the circuit, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0382?+
Yes once the engine is running, but cold starts will be hard and smoky. Fix it before cold weather to avoid no-starts.
Can I just clear P0382?+
You can, but it returns until the failed glow plug or circuit fault is repaired.
Related codes
Often seen with P0382
Read & clear P0382 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