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P0382 is a diagnostic trouble code (DTC) for "Glow Plug / Heater Circuit "B" Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
The P0382 code being stored by a vehicle’s PCM means that the glow plug for a diesel engine has malfunctioned.
Diesel engines don’t just consume a different type of fuel than the kind necessary for more conventional vehicles. They actually function a lot differently too. One example of this is the need for a glow plug. When an owner goes to start their diesel engine, the PCM (Powertrain Control Module) immediately takes a reading on the temperature of the engine.
If it finds that the temperature is too low, a glow plug is used to heat up the cylinder temperatures so that the diesel fuel will have an easier time igniting. These glow plugs will literally glow red hot in order to achieve the needed temperature for this to happen.
In some vehicles, the PCM will actually keep the glow plugs going after the engine has started. Manufacturers elect for this option when they want to reduce engine noises or simply the production of white noise.
When the P0382 code is stored by the PCM, it’s because it’s detected a problem with the glow plug heater circuit B which is keeping it from working properly.
There are four main reasons that could cause this problem to occur. They are:
In very rare cases, the PCM may actually be the thing that is faulty. Don’t go about trying to repair or replace it, though, until you’ve exhausted every other option.
Generally, if this trouble code is logged, the driver should see their check engine light come on. Other reliable signs would be:
This last one is the most common indicator. You may experience one or both of the other two too, but if your vehicle is easy to start, it’s probably not a P0382 problem.
If a mechanic is working on a vehicle with a P0382 code logged, they will most likely follow this path to a resolution:
As the problem always involves the glow plug, simply tracing the steps between it and the starter is usually enough to find the problem.
The glow plug is no doubt important to finding the source of the P0382 code, but don’t just stop there. For example, you may notice there’s an issue with the relay. Address that, but continue your search for any other potential problems, especially if there were related codes found when the OBD-II scanner was used.
This isn’t the type of problem that will cause you to end up off the road, but it will keep you from getting on the road in the first place. If you live in a cold environment, a P0382 problem could mean your car stays still for a very long time.
Some kind of replacement will almost surely be necessary. Whether it’s the glow plug itself, the wiring, connectors, etc. something is going to get changed out.
Related codes like P0380, P0381, P0383 and P0384 are commonly present along with this one.
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