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DTC/P0380

P0380: Glow Plug / Heater Circuit "A" Malfunction

Quick Answer
Bassa GravitàSicuro da guidare (a breve termine)Impianto elettrico

P0380 is a diesel-only code meaning the engine control unit detected a fault in glow plug heater circuit "A" (the main glow plug circuit or its control relay). Glow plugs preheat the combustion chambers so a cold diesel can ignite. The ECU monitors the circuit for open or shorted wiring and a failed glow plug relay or module. Repairs typically run 60-400 EUR depending on whether a relay, wiring, or full plug set is needed.

Costo di riparazione stimatoDa €2 a €480+, varia in base al veicolo

Cosa significa P0380?

P0380 is a diesel-only code meaning the engine control unit detected a fault in glow plug heater circuit "A" (the main glow plug circuit or its control relay). Glow plugs preheat the combustion chambers so a cold diesel can ignite. The ECU monitors the circuit for open or shorted wiring and a failed glow plug relay or module. Repairs typically run 60-400 EUR depending on whether a relay, wiring, or full plug set is needed.

P0380 è un codice diagnostico di guasto relativo a impianto elettrico, classificato con gravità low. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0380 e accende la spia motore.

Quali sono i sintomi di P0380?

Se il tuo veicolo ha attivato P0380, potresti notare uno o più di questi sintomi:

  • Check engine light or glow plug indicator illuminated
  • Hard or extended cranking when starting cold
  • White or grey smoke from the exhaust on cold start
  • Rough idle and misfire for the first minute after a cold start
  • Reduced cold-weather startability, worse as temperatures drop
  • Will likely fail a diesel emissions or technical inspection

Cosa causa P0380?

Ecco le cause più comuni di P0380, ordinate in base alla probabilità che siano la causa del problema:

altaFailed glow plug relay or glow plug control module
altaOne or more failed glow plugs (open circuit)
mediaCorroded or broken wiring/connectors in the glow plug harness
mediaBlown glow plug system fuse
bassaPoor ground connection to the glow plug circuit
bassaFaulty ECU glow plug driver output (rare)

È sicuro guidare con P0380?

In genere sì, per brevi tragitti. Safe to drive once the engine is warm. The glow plug system only assists cold starting on diesel engines, so the engine runs normally after warmup. Expect harder, longer cranking on cold mornings and more white smoke at startup. The car will likely fail a diesel inspection with this code stored.

Come si diagnostica P0380?

Segui questi passaggi per individuare la causa principale di P0380:

  1. Read the stored code and freeze frame with Skanyx or any ELM327 adapter to confirm P0380 and note the temperature at which it set
  2. Check the glow plug system fuse and relay first, as a blown fuse or failed relay sets this circuit-level code
  3. With the ignition off and glow plugs disconnected, bench-test each plug with a multimeter: a healthy glow plug reads roughly 0.5-2 ohm, while an open (infinite) reading means that plug has failed
  4. Inspect the glow plug harness and connectors for corrosion, broken pins, or chafed wiring
  5. Verify the relay/control module sends battery voltage to the plugs during the preheat cycle with a multimeter on the supply side
  6. Note that per-cylinder glow plug live status is manufacturer-extended (Mode $22) data and is not available over generic OBD2, so the multimeter bench test is how you find the specific failed plug

Quanto costa riparare P0380?

I costi di riparazione di P0380 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace glow plug system fuse (DIY) €2–€8 €0–€0 €2–€8 Facile
Replace a single glow plug (DIY) €10–€30 €0–€0 €10–€30 Moderata
Replace glow plug relay/control module (shop) €40–€180 €50–€130 €90–€310 Moderata
Replace full glow plug set plus relay (shop) €80–€260 €90–€220 €170–€480 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

P0380 su veicoli specifici

P0380 si comporta in modo diverso a seconda del tuo veicolo. Seleziona la tua auto qui sotto per cause specifiche del modello, problemi noti e stime dei costi adeguate:

Volkswagen

P0380 su Volkswagen Golf TDI

2005-2021

The Golf TDI commonly sets P0380 from a failed glow plug control module or aged plugs around 120,000-180,000 km. On many TDI engines the glow plug controller is a smart module that monitors each plug, so a single open plug can flag the circuit. Access is reasonable but the plugs can seize if they have never been changed, so a workshop with proper extraction tools is recommended on high-mileage cars.

Cosa causa P0380 su una Volkswagen Golf TDI?

Volkswagen Golf TDIFailed glow plug control module on TDI engines
Volkswagen Golf TDISeized glow plugs on high-mileage cars that have never been serviced

Costo di riparazione di P0380 per Volkswagen Golf TDI

Costi stimati per i proprietari di Volkswagen Golf TDIadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Volkswagen

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace glow plug system fuse (DIY) €2–€8 €0–€0 €2–€8 Facile
Replace a single glow plug (DIY) €11–€32 €0–€0 €11–€32 Moderata
Replace glow plug relay/control module (shop) €42–€189 €53–€137 €95–€326 Moderata
Replace full glow plug set plus relay (shop) €84–€273 €95–€231 €179–€504 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

BMW

P0380 su BMW 320d

2005-2019

BMW diesels (M47, N47, B47) use a glow plug control module that reports circuit faults. On the N47, access to the glow plugs is tight and seized plugs are common, which raises labor. P0380 here is usually the control module or aged plugs. Per-cylinder glow plug status on BMW lives on Mode $22 extended data and needs a BMW-specific tool such as Carly, not generic OBD2.

Cosa causa P0380 su una BMW 320d?

BMW 320dGlow plug control module failure on N47/B47 engines
BMW 320dSeized plugs increasing labor on tight N47 cylinder head access

Costo di riparazione di P0380 per BMW 320d

Costi stimati per i proprietari di BMW 320dadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici BMW

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace glow plug system fuse (DIY) €3–€11 €0–€0 €3–€11 Facile
Replace a single glow plug (DIY) €14–€41 €0–€0 €14–€41 Moderata
Replace glow plug relay/control module (shop) €54–€243 €68–€176 €122–€419 Moderata
Replace full glow plug set plus relay (shop) €108–€351 €122–€297 €230–€648 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Audi

P0380 su Audi A4 TDI

2004-2019

The A4 TDI shares VAG glow plug architecture with the Golf and uses a monitoring control module. P0380 typically points to the module or aged plugs at higher mileage. Some 2.0 and 3.0 TDI engines run ceramic glow plugs that are more fragile and snap if removed cold, so warm removal and care are important to avoid a far costlier head repair.

Cosa causa P0380 su una Audi A4 TDI?

Audi A4 TDIGlow plug control module fault on VAG TDI engines
Audi A4 TDIFragile ceramic glow plugs snapping during removal on some 2.0/3.0 TDI

Costo di riparazione di P0380 per Audi A4 TDI

Costi stimati per i proprietari di Audi A4 TDIadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Audi

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace glow plug system fuse (DIY) €2–€9 €0–€0 €2–€9 Facile
Replace a single glow plug (DIY) €12–€35 €0–€0 €12–€35 Moderata
Replace glow plug relay/control module (shop) €46–€207 €57–€150 €103–€357 Moderata
Replace full glow plug set plus relay (shop) €92–€299 €103–€253 €195–€552 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Mercedes-Benz

P0380 su Mercedes-Benz (OM651 diesel)

2008-2018

The OM651 four-cylinder diesel uses a glow plug control module that the ECU monitors for circuit faults. P0380 on the OM651 is commonly the module or worn plugs. Mercedes glow plug data beyond the generic circuit code is manufacturer-extended and needs XENTRY or a Mercedes-capable tool. Plug access is moderate but the plugs can seize on neglected engines.

Cosa causa P0380 su una Mercedes-Benz (OM651 diesel)?

Mercedes-Benz (OM651 diesel)Glow plug control module failure on OM651
Mercedes-Benz (OM651 diesel)Worn or seized plugs on neglected high-mileage engines

Costo di riparazione di P0380 per Mercedes-Benz (OM651 diesel)

Costi stimati per i proprietari di Mercedes-Benz (OM651 diesel)adeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Mercedes-Benz

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace glow plug system fuse (DIY) €3–€10 €0–€0 €3–€10 Facile
Replace a single glow plug (DIY) €13–€39 €0–€0 €13–€39 Moderata
Replace glow plug relay/control module (shop) €52–€234 €65–€169 €117–€403 Moderata
Replace full glow plug set plus relay (shop) €104–€338 €117–€286 €221–€624 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Questi codici compaiono spesso insieme a P0380 o indicano problemi correlati:

Domande frequenti su P0380

Can I drive with a P0380 code?

Yes. Glow plugs only help a cold diesel start, so once the engine is warm it runs normally. You will get harder cold starts, more startup smoke, and the car will likely fail inspection until the fault is fixed.

Will a bad glow plug stop my diesel from starting?

Usually not in mild weather. A warm engine or warm climate often starts fine with one or two dead glow plugs. In cold weather, multiple failed plugs can cause long cranking, heavy white smoke, or a no-start.

How do I find which glow plug is bad?

Disconnect each plug and measure its resistance with a multimeter. A good glow plug reads about 0.5-2 ohm. A plug that reads open (no continuity) has failed. Generic OBD2 only gives you the circuit code, not per-plug status.

Is it worth replacing all glow plugs at once?

Often yes. Glow plugs age together and most of the labor is gaining access. If one has failed at high mileage, replacing the full set avoids a second job when the next plug fails soon after.

Why does my diesel smoke white on cold start with this code?

Without working glow plugs the cold combustion chambers cannot fully ignite the diesel, so unburned fuel leaves the exhaust as white smoke until the engine warms up. The smoke clears once the engine reaches operating temperature.

Leggi le nostre guide dettagliate

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