Why Does My Apu Keep Shutting Off? Important Things To Know

We have heard some people ask, “Why does my APU keep shutting off?”

Perhaps you are a trucker who spends more time in the truck during long hauls. You spend hours inside your vehicle whether relaxing, sleeping, or listening to the radio.

This is why it only makes sense to have a comfortable space where you can do all of these in your truck. And so, the APU needs to be working well to keep you cool while in your vehicle.

If you encounter issues with your APU, it is worth looking into why it happens and what you can do about it. Let’s get started.

why does my apu keep shutting off

Why Does My APU Keep Shutting Off?

First of all, let us look into what the APU does, the different types available, and what causes it to shut off.

The Auxiliary Power Unit or APU is a power generator on 18-wheel vehicles. This power generator provides your vehicle with energy for using the heater, AC, TV, and other electrical appliances without keeping your truck in an idle mode. Hence, you can save money on diesel fuel.

In fact, the APU allows you to save up to 0.25 in an hour. Moreover, the APU also minimizes air pollution and makes it much easier for you to comply with the state’s idling regulations and laws.

There are different types of APUs for trucks. Here are just some of them.

1. Combustion APU

When you have fuel in your APU, you can expect a relatively unlimited power supply. This type of APU is also quite strong and efficient for heating or cooling larger vehicles. You can run your microwave and use your TV.

The only downside is that it is a maintenance-heavy type of APU. It also requires frequent oil changes, general preventative maintenance for clamps, valves, and hoses, and fuel filters.

2. Electric APU

With an electric APU, there is a more finite power supply. It is battery-powered and allows you to operate your AC for up to 12 hours and then a bit more power left for heating. When it comes to charging the battery, expect between 6 and 12 hours for you to do this.

But with an electric APU, you can expect less maintenance work. Only some regular electrical connection upkeep and replacing the battery are all you need to keep the APU running.

Now that you know more about APUs and what they do, let us talk about one common issue with it. Sometimes, you may experience your APU shutting off repeatedly. So, why does this happen, anyway?

APUs have smaller diesel engines with diesel exhaust aftertreatment systems. These units also need periodic maintenance such as DPF regeneration, to name a few. You need to have the regeneration done while your truck is in motion. This is why it is convenient to do, as long as regeneration warnings are strictly followed to ensure safety.

When regeneration is not done, it can cause issues with the APU. Issues that arise include shutting off frequently, which is why you need to have this maintenance work scheduled to keep the unit running well.

It is also worth noting that there are factors that can alter the length of time between each aftertreatment regenerations such as oil consumption and fuel quality. When there is poor quality of fuel, exhaust that is produced has more unburned carbon. This will then accumulate in your diesel particulate filter, which increases pressure. Once the sensors detect a need for a shorter regeneration cycle, then an alert will be sent out.

Furthermore, if the lubrication oil is being burned more quickly by your engine, the soot from the oil triggers shorter regeneration cycles.

Read More: Why Does My Truck Smell Like Rotten Eggs? Common Causes You Need To Know

Final Thoughts

Overall, it is important to make your APU service a part of your vehicle’s maintenance. By making sure that it is well-maintained, you can prevent issues such as shutting off constantly, which can be a hassle and inconvenience you would not want to experience.

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