Glow Plug/Heater Circuit A
What it means
P0380 is a diesel code meaning the engine computer sees a fault in the glow-plug (intake/preheat) circuit A. Glow plugs warm the combustion chambers so a cold diesel will start; with a bad circuit, cold starts can be hard, rough, and smoky, though a warm engine usually runs normally. It's typically a burnt-out plug, wiring, or the control module.
Can I keep driving? A warm engine drives normally, but cold starts can be hard or fail entirely in cold weather until the glow-plug circuit is repaired. This is a diesel-only code.
Real-world scan data
Appears alongside · share of P0380 scans
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on (and often a glow-plug indicator light)
- Hard starting when the engine is cold
- Rough running or white smoke just after a cold start
- Little or no effect once the engine is warm
Common causes
Most likely first
- Burnt-out or open glow plug(s)Likely
- Damaged or corroded wiring in the glow-plug circuitCommon
- Loose or corroded electrical connectionsCommon
- Failed glow-plug control moduleLess often
- Failed ECM (rare — check plugs and wiring first)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm which glow-plug circuit set the code.
- Inspect the glow-plug wiring, feed strap, and connectors 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 its supply/ground.
- Repair the circuit or replace failed plugs, then clear and re-test with a cold start.
FAQ
Quick answers
Is it safe to drive with P0380?+
Can I just clear P0380?+
Related codes
Read & clear P0380 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.