Glow Plug/Heater Circuit "A"
The DURAMAX-P0380 (Duramax) diesel fault code means: Glow Plug/Heater Circuit "A". This is a moderate severity code.
- Keep driving?
- Yes, with caution
- DIY difficulty
- easy
Down with a Duramax fault on the road?
We are building a network of verified mobile diesel and reefer technicians along the freight corridor. It is not live yet — no one can be dispatched to you today. You can see where the pilot is launching and register interest.
View pilot availability →A $30 car code reader can't do diesel. The HD7000 reads full-system codes and does parked DPF regen, idle/speed-limit, and service resets from the cab — on everything from a 6.7 Cummins/Power Stroke/Duramax pickup to Class-8 trucks (Detroit, Paccar, CAT, Volvo, Mack, International).
Full-system 6/9/16-pin diesel scan tool for Cummins, Paccar, CAT, Detroit and more — plug-and-play, no subscription. A cheaper way to read heavy-duty codes a basic OBD2 scanner skips entirely.
Affiliate links — we earn a commission at no extra cost to you.
What Are the Symptoms of DURAMAX-P0380?
- Check Engine Light on
- Hard starting when cold
- White smoke after a cold start
What Causes DURAMAX-P0380? (Most Likely First)
- Failed glow plug relay or controller High
- Damaged wiring or connector in the glow plug circuit High
- Failed glow plugs Moderate
Can I Still Drive with DURAMAX-P0380?
Yes, with caution. DURAMAX-P0380 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Common Fixes by Vehicle
What techs usually find when diagnosing DURAMAX-P0380 on specific platforms — tap a platform for the fix and the exact part:
2001-2016 GM 6.6L Duramax Moderate DIY
Glow plug relay (also called glow plug controller module) has failed. On LB7/LLY it's mounted on the passenger valve cover. Check for 12V command from ECM and output to plugs. If command is present but no output, replace the relay/module.
Labor: 1.0 hrFrequently Asked Questions
What does P0380 mean on a Duramax?
P0380 means Glow Plug/Heater Circuit "A". The engine computer has detected a fault in the glow plug or heater circuit "A".
Is P0380 a Duramax-specific code?
No. P0380 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions GM uses to set it on its diesels are in GM service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose DURAMAX-P0380?
Command the glow plugs with a scan tool and check for voltage at the plugs.
Check the relay or controller and its power supply.
Measure the glow plug resistances.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines P0380 as a generic OBD-II code)
P0380 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
Explore More
Was this helpful?
Send this to whoever is fixing the truck — your tech, or the person asking what the fault means.