P0380 on GMC
Glow Plug/Heater Circuit A Malfunction
P0380 on GMC vehicles indicates glow plug/heater circuit a malfunction. Au7o has documented this code across 1 GMC model — most commonly on Sierra 3500HD. P0380 applies to diesel engines and means the computer detected a malfunction in glow plug heater circuit 'A'. Glow plugs preheat the combustion chambers to help a cold diesel start, and the control module monitors the glow plug circuit (often through a relay/control module); when the current or voltage isn't what it expects, it sets this code. The most noticeable symptom is hard cold starting, rough running until warm, or extra white smoke at startup. It indicates an electrical fault in the glow plug system rather than a fuel-injection problem. Typical repair costs on GMC range from $250 to $1,200, depending on the specific model and root cause.
Common Causes of P0380
- •One or more failed glow plugs
- •Faulty glow plug control module or relay
- •Corroded or loose glow plug wiring/connectors
- •Open or shorted glow plug circuit wiring
- •Blown glow plug fuse
- •Poor power feed or ground to the glow plug circuit
- •Failed driver in the engine control module
P0380 on GMC by Model
GMC Sierra 3500HD(1 issue)
- Glow plug control module / glow plug circuit faults causing hard cold starts (Duramax)2007-2019
Duramax-equipped Sierra 3500HD owners report hard starting, extended cranking, and rough idle in cold weather due to glow plug system faults. NHTSA complaints and service information commonly involve failed glow plugs, glow plug control module issues, or wiring/connector problems that trigger circuit DTCs and reduce preheat performance.
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View P0380 across all makes →Frequently Asked Questions
What does P0380 mean on GMC?▼
P0380 stands for "Glow Plug/Heater Circuit A Malfunction." P0380 applies to diesel engines and means the computer detected a malfunction in glow plug heater circuit 'A'. Glow plugs preheat the combustion chambers to help a cold diesel start, and the control module monitors the glow plug circuit (often through a relay/control module); when the current or voltage isn't what it expects, it sets this code. The most noticeable symptom is hard cold starting, rough running until warm, or extra white smoke at startup. It indicates an electrical fault in the glow plug system rather than a fuel-injection problem. On GMC specifically, this code is documented across 1 model.
What causes P0380 on GMC vehicles?▼
Common causes on GMC: One or more failed glow plugs, Faulty glow plug control module or relay, Corroded or loose glow plug wiring/connectors, Open or shorted glow plug circuit wiring, Blown glow plug fuse. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0380 on a GMC?▼
Repair costs on GMC range from $250 to $1,200, depending on the specific model and root cause.
Which GMC models have P0380 documented?▼
Au7o has documented P0380 on 1 GMC model: Sierra 3500HD.