LG Dryer d90 Code – What it means And How To Fix It

An LG dryer d90 code indicates that there is a 90 percent blockage in the vent hose or vent line. However, there are a couple of other possibilities that could be causing a d90 code – a faulty heating element or thermal fuse.

Modern dryers can be efficient but their computer error codes can be confusing sometimes. Most of the time, problems with a dryer can be easily resolved without calling a technician. You can diagnose many things yourself. 

This may take a little outside-the-box thinking to solve, but is one of the problems you can very likely diagnose and remedy yourself. 

The article below will explain all you need to know about resolving the problem. 

What the LG Dryer d90 Code Means

Your LG dryer has a Flow Sense feature that uses four illuminated display bars to clue you in to the airflow efficiency while it’s running.

This display monitors clogs in the vent line and will show you the degree of your airflow restriction. It will light up one bar for each 20% of blockage. 

So, with one bar lit, you have approximately 20% blockage and 80% flow. With two bars, 40% blockage, and so on.

Once you get to four bars, your display will show a d80 code, which, of course, means you have 80% restriction in your vent. Yet, the dryer will still run at that low level of airflow.

However, as you exceed 80% and hit 90%, a d90 code will pop up and the dryer will begin to cool down and turn off.

The LG dryer has a built-in self-protection feature in order to keep it from overheating. This is because the main cause of dryer fires is too much lint buildup.

Once the dryer has cooled down, and the blockage removed, it will run like normal again.

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Read: LG Dryer Flow Sense – What It Is And How It Works?

Troubleshooting Steps

To resolve this LG dryer code d90, the first thing to do is figure out where the blockage is. It could be as simple as an overstuffed lint trap, or as difficult as a crushed vent pipe, among other things. 

Before doing anything else, unplug the dyer

Check The Lint Filter

The best plan of action is to start at the dryer’s front portion and work toward the back, as you check for clogs and debris. That means the first thing to check is the lint filter. Lift it out to make sure it’s clean. That is probably not your problem but an excessively dirty lint filter will certainly affect airflow. 

Related: 6 Reasons Why LG Dryer Won’t Start

Look at the Exhaust Hose

The next thing to check is the exhaust hose. This is the 4-inch hose that runs from the dryer’s back to the wall vent. Lint may have nearly blocked all airflow. Also, make sure the vent hose isn’t kinked or twisted

You can disconnect the hose from the dryer to check it. Be sure to disconnect the hose from the wall inlet, also. That way, you’ll be able to blow into the hose to clear it. For this, you can use a hair dryer, a shop vacuum on reverse, a leaf blower, or even an air compressor.

You can also take a snake or a broom handle and carefully run it through the hose to clear any clogs. 

Check the Wall Duct

Look inside the wall inlet. Can you see any accumulated lint and debris? If so, remove anything you can reach by hand.

This is another place you can use a blower device to attempt to clear out the ducting. A shop vacuum on reverse (so it blows instead of sucks) or a leaf blower works great for this.

However, it would be a good idea to first check the outside vent to see where the lint will blow out. You don’t want to make a huge mess in your yard or on your roof.

Have a helper hold a trash bag in front of the vent to catch most of the debris that might shoot out.

Look at the Outside Vent

The outside vent is what allows the inside heat and air from the dryer to escape the house. It is attached to the vent you found in the wall. 

In most homes, the outside vent is directly opposite the inside wall vent on the side of the house. Most homes are set up where the dryer’s location is along an exterior wall so there is only a short distance to run the outside vent. 

However, some homes do have roof vents so you may have to look to find yours if you don’t already know where it is. 

Look immediately inside the lint vent to see if there is a collection of debris that makes airflow difficult. You can clean this out by hand or with a small tool to scrape or pull lint out. 

Since outdoor vents are subjected to the weather, some of the lint and dirt may have become hardened which could be what is closing off airflow. It may be a little difficult to retrieve it from the vent.

In fact, you may need to remove the grille or louvers in order to get all of the lint out. And if it’s hardened, try softening it with some water and use a small brush.

Read: Why Is LG Dryer’s Steam Fresh Cycle Not Working?

Resetting the Dryer

Once you have followed these steps, you can plug the dryer back in. It should reset and clear the LG code d90 once it’s plugged in. Don’t reconnect the hose yet. There is one more thing to do.

Troubleshooting Test

See if your clothes are still wet. If they are, turn the dryer back on without the vent hose to see if they dry within an appropriate period.

If your clothes were mostly dry when the error occurred, you will need to remove them and put in some wet clothes from the washer. Turn it on to see how they dry. If they dry within the normal time frame, then your clog has to be in the exhaust. 

A good test result (one that shows the clothes are drying) means you can turn off the dryer and reconnect the vent hose. Run a load of wet clothes in a new round to see if they dry as well as the first load. 

If they dry well without the error code showing up, then you’ve fixed your problem. 

Clothes that don’t dry or that take too long to dry indicate you could have a failing heating element or thermal fuse. See the next section below.

Read: Top 5 Common LG Dryer Problems

What If There Isn’t a Blockage?

There is a possibility you could get a LG dryer code d90 even though you have no blockage at all.

Those who do all of the steps above and find there isn’t a blockage may have a bad element or fuse. While that code is for a blockage, some experts say a bad heating component could possibly trick the sensor into thinking there’s a blockage.

If you’re positive that the vent line is clean and clear – all the way out to the outside – then you’re going to need to investigate your dryer components further. This means accessing and testing your heating element and fuse.

Here are a couple of articles that should help you through the next steps:

LG Dryer Not Heating – Possible Issues And Solutions

What’s The Cost To Replace The Heating Element In A Dryer?


Can I just reset the dryer to fix the error?

While resetting the dryer will eliminate many errors, it will not reset the Flow Sense error until you’ve cleared any blockages from the lint filters and exhaust system. The air must flow correctly again in order to get rid of the LG d90 code.

Why am I seeing Flow Sense flashing?

This is the advanced warning system that draws your attention to anything going wrong with the household ductwork or hose to the dryer. An alert means you need to stop and clean the system. 

How Do I Know If a Clog Is beginning to Grow?

There are signals that you are developing a clogged dryer vent even before the first Flow Sense alert is activated.

  • There will be excessive drying times. This is a key first indicator of a problem if the clothes aren’t fully drying as they once did in a normal cycle. 
  • You may also notice a burning smell coming from the dryer. This can happen when clothes are running through a long drying cycle.
  • The interior of the dryer is extremely hot, indicating it is running harder than it’s supposed to run.
  • You keep pulling a lot of lint from the lint trap – more than normal.

All of this means you should go ahead and check your hose and ductwork before the light comes on. 

Read: Dryer Smells Like Burning?

When should dryer vents be cleaned?

You should clean out your dryer vents annually. It depends on how much laundry you do. Those who have larger families and do a lot of laundry loads may need to clean out their dryer vents twice a year or more.

Read: How Often Should I Clean My Dryer Vent?

Dryer Safety

Allowing lint to accumulate in the hose, lint trap and duct is a fire hazard. Lint can eventually get hot behind the dryer and catch fire. Many home fires start because of a dryer clogging issue.

This is why the Flow Sense system was created to alert you to clogs before they become a safety issue. Taking a preventative approach by cleaning and checking your system regularly, is an easy way to have peace of mind.

Read: LG Dryer Error Code D80 D90 D95 – How To Fix It?

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