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.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Glow plug indicator
- Indicator wiring
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Indicator bulb or LED failed
- Wiring or connector fault
Possible 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
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.