Glow Plug / Heater Circuit 'A' Malfunction
The DURAMAX-P0380 (Duramax) diesel fault code means: Glow Plug / Heater Circuit 'A' Malfunction. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $250-$700
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Common Symptoms
- Rough idle or stalling (CKP/CMP)
- Hard start in cold weather (glow plug)
- Check Engine Light
- Loss of power or poor throttle response
- Fluctuating RPM at idle
Probable Causes (Ranked by Likelihood)
- Glow plug controller failure Very Likely
- Damaged wiring or corroded connector Likely
- Contamination of sensor (MAF dirt) Possible
- PCM / ECM driver fault Less Likely
Step-by-Step Diagnostic Procedure
Read freeze frame data to identify operating conditions when fault set
Back-probe the sensor with a DMM and verify signal voltage against spec
Clean or replace MAF sensor with OEM part (aftermarket MAFs often cause repeat codes on Duramax)
Inspect harness for abrasion or damage near sensor mounting point
Clear code and monitor — recurring fault indicates sensor or wiring replacement
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 is P0380 on a Duramax?
Duramax code P0380 (Glow Plug / Heater Circuit 'A' Malfunction) is a moderate-severity diagnostic trouble code triggered by the engine control module when it detects a problem in the associated system. Always use OEM or ACDelco sensors on Duramax — aftermarket sensors frequently trip repeat codes.
Is a Duramax P0380 safe to drive?
Usually yes for short trips. Fix soon to restore driveability and avoid triggering additional system faults.
How much does it cost to fix P0380 on a Duramax?
Repair cost $250-$700 — typically a DIY job in an hour or two.
P0380 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown: