P0381 code meaning
Glow Plug/Heater Indicator Control Circuit/Open
Powertrain system Generic code P03xx codes Check engine light
What P0381 means
P0381 monitors the circuit of the wait-to-start lamp for an open circuit or, more generally, for faults that keep the lamp dark when commanded – CARB names a burnt-out bulb as the example, with exemptions for LCD clusters and for engines that only release the starter after preheating. GM's 2015–2018 diesels detect an open circuit in the driver by a high load impedance (about 200 kΩ in 2015), in 0.2 s or 10 of 15 samples, with the check engine light after two trips; on the 2014 Duramax LML P0381 still covered all lamp circuit faults including a short to ground. Ford's 2023 diesels check via the instrument cluster: if it reports the lamp off although on is commanded, P0381 is set within about 1 s at key-on. There is no limp mode; the risk is starting too early in the cold.
P0381 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0381
- Glow plug light does not come on at key-on
- Check engine light on (GM after two trips)
- Driver starts too early in the cold
Common causes of P0381
- Most likelyControl wire open or connector fault between engine module and cluster
- PossibleLamp or LED in the instrument cluster burnt out
- Less likelyInstrument cluster faulty or communication problem (Ford)
- Less likelyDriver in the engine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Glow plug indicatorIndicator wiringInstrument clusterEngine control module
What each part of P0381 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3 | Area: ignition system or misfire. |
| 81 | The exact fault in that area. |
What to do next
- Note P0381 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0381
What does P0381 mean?
P0381 means "Glow Plug/Heater Indicator Control Circuit/Open". P0381 monitors the circuit of the wait-to-start lamp for an open circuit or, more generally, for faults that keep the lamp dark when commanded – CARB names a burnt-out bulb as the example, with exemptions for LCD clusters and for engines that only release the starter after preheating. It is a generic code, so it means the same on every make.
Is it safe to drive with P0381?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0381 fail an emissions test?
Yes, it can. P0381 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0381 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P0381 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.