Fault codeP0380

SEVERE

Glow Plug/Heater Circuit A Malfunction

What this code means

Glow Plug/Heater Circuit A Malfunction.

P0380 is a generic code: it means the same thing on every make. P0380 belongs to family P03xx — Ignition and misfire. Its page explains how to read a code and groups all its codes by part.

Glow plugs (diesel)

Glow plugs heat the combustion chambers of a diesel engine so that it starts in the cold, and on many engines they keep heating for a few minutes afterwards to reduce smoke and noise. A control unit or relay feeds them and checks their circuit.

Symptoms

On diesels: hard or impossible starting in cold weather, white smoke and a shaking engine for the first seconds, glow plug light staying on or flashing. The control unit detected a fault in the preheating circuit — one or more glow plugs, the relay or the wiring.

Common causes

One or more burnt-out glow plugs — they wear and are replaced as a set
Failed glow plug relay or control module
Blown preheating circuit fuse
Corroded glow plug supply cable or bus bar
Damaged loom or failed ground

How to diagnose it

Test each plug with a multimeter, ignition off and supply cable removed: the resistance should be very low, around 0.5 to 2 ohms. Infinite resistance means a burnt-out plug. On many engines, one dead plug does not stop summer starting but makes winter starting a chore.

If all the plugs are good, check for 12 V at their bus bar, ignition on during preheating: absent, the relay or its fuse is at fault.

What to do

Have it checked promptly. A misfire sends unburnt fuel into the exhaust and destroys the catalytic converter within a few dozen kilometres. If the light is flashing, stop driving.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

Repair cost

Glow plug: €10 to €40 each, usually replaced as a set of four: €100 to €250 fitted. Beware of seized plugs that snap on removal. Glow plug relay: €40 to €150.

How to read this code

PPowertrain
0standardised code
3Ignition and misfire
80P0380