P0381
Glow Plug/Heater Indicator Circuit Malfunction
Electrical fault in the glow plug indicator lamp or relay circuit. The ECU monitors driver feedback to ensure the dashboard indicator can be commanded; an open or shorted circuit triggers this code.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Symptoms
- Glow plug warning light on (often orange coil symbol)
- Hard cold start or no start in cold weather
- White smoke from exhaust during warm-up
Common causes
Ordered by how often each turns out to be the cause.
- Indicator bulb or LED failedPossible
- Wiring or connector faultPossible
Parts involved
- Glow Plug Indicator
- Indicator Wiring
P0381 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.