P0381 Code: Glow Plug/Heater Indicator Circuit

It’s difficult to start up your engine after a cold night. Glow plugs speed up the process by increasing the temperature in your engine’s combustion chambers. P0381 is one of the trouble codes related to a fault in the glow plug/heater indicator circuit.

What Does the P0381 Code Mean?

Diagnostic trouble code (DTC) P0381 stands for “Glow Plug/Heater Indicator Circuit.”

This code is logged on vehicles with diesel-powered engines.

The powertrain control module (PCM) monitors and retrieves information like coolant temperature when you start your engine. It does this to check if your engine is hot enough to function properly.

With a diesel-powered engine, once the PCM detects that the temperature isn’t enough, it’ll trigger the engine’s glow plugs. The glow plugs raise the temperature in the cylinders, making it easier for combustion to take place.

The glow plugs are equipped with a heater control circuit that has a glow plug indicator. The indicator functions as a warning light that turns on when the glow plugs operate. In cold start conditions, the indicator usually illuminates after the ignition switch is turned on. It normally goes off before the engine starts.

When the PCM detects a fault in the glow plug indicator circuit, it’ll trigger the P0381 code. A malfunction indicator lamp might also be illuminated.

Note: The definition of code P0381  might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0381 Code?

• Defective glow plug indicator lamp bulb
• Controller issues
• Glow plug/heater indicator circuit issues (open or shorted)
• Faulty instrument panel circuit board

What are the Common Symptoms of the P0381 Code?

• Illuminated check engine light
• Glow plug indicator won’t illuminate
• Glow plug indicator won’t turn off

How to Diagnose the P0381 Code

DTC P0381 can be logged on various vehicles. However, this doesn’t mean that the steps for diagnosis and repair are the same for all makes and models.

If you’re not familiar with vehicle repair, it might be best to have a professional diagnose the problem. But if you’re an experienced automotive DIYer, then you can go ahead and take on the challenge.

How to Fix the P0381 Code

Fixing the P0381 code can be frustrating and complicated. If you’re not familiar with glow plugs and how they work, you can always take your ride to an auto repair shop for repairs.

But if you have the tools and technical know-how to get the job done, you can try and fix the problem yourself. However, keep in mind that there’s no universal solution for this error code. So it’s important to read up on vehicle-specific repair information.

Guides like the ones from Chilton can help you with your repair. You can also get an ALLDATA subscription to help you find vehicle-specific repair steps.

Replace Your Faulty Glow Plug Controller Today

The last thing you want is to ignore a faulty glow plug controller. Aside from triggering the P0381 code, it can also cause the glow plug indicator light to turn on. Some cars won’t fully start until the light has turned off, while others might go into “safety mode” with limited performance. This can negatively affect your vehicle’s driveability, making it unpredictable. For your own safety, it’s best to replace your faulty glow plug controller as soon as possible. Luckily, getting a new one is fast and easy with CarParts.com.

As a one-stop shop for OE-grade parts, CarParts.com offers a wide selection of high-quality glow plug controllers. The best part is you won’t have to wait too long before your order arrives. If you order by 12 PM ET, you can expect your new glow plug controller to arrive in as fast as two business days. Thanks to our strategically located warehouses around the US, you can get back on the road in no time.

Don’t wait until your defective glow plug controller completely breaks before replacing it. Check out our wide selection of glow plug controllers at CarParts.com and get a replacement today!