P0380: Glow Plug/Heater Circuit A
What to do
You may notice nothing in warm weather. Expect hard cold starting, extended cranking and white smoke as temperatures drop. Worth repairing before winter rather than after — and be aware that seized plugs can make what looks like a small job considerably larger.
What this code means
A fault in the glow plug circuit. Glow plugs heat the combustion chamber so a cold diesel will fire — compression alone is not enough below a certain temperature, and the colder it is the more they matter. In mild weather a diesel with dead glow plugs may start almost normally, which is why the fault often goes unnoticed until the first genuinely cold morning.
Glow plugs fail individually and progressively, so the symptom scales: one dead plug gives a slightly rougher cold start, several gives extended cranking and white smoke, all of them gives a no-start in the cold. Because they are consumable and tend to seize in the head with age, removal is frequently the hard part of the job rather than diagnosis.
Likely causes
Start here
- Failed glow plug · moderate
- Failed glow plug control module · moderate
- Corroded or loose connector · easy
- Blown fuse supplying the glow plug circuit · easy
Less common
- Open circuit in glow plug wiring · moderate
- Faulty engine coolant temperature sensor · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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