Struggling with the nightmarish Dyson air quality sensor problem? Try the simple quick fix in this troubleshooting guide

Dyson Pure Cool is essentially part air purifier, part fan (Dyson offers a tabletop or desktop version too), and part air quality sens0r.

And the sensor it uses to constantly monitor air quality where it has been placed is remarkably accurate.

But, it is not infallible and that is why users struggle with the stubborn Dyson air quality sensor problem (the fan reads 999 severity for PM10 and PM2.5 values even when you’re sure that the air quality is better).

The good news is that this is an issue you can easily troubleshoot even if you are not mechanically inclined.

Let’s first look at the causes of the annoying issue..

Causes of the Dyson air quality sensor problem

According to Dyson, the error occurs when the sensor (or circular amp in some cases) becomes blocked- dust is one of the most common culprits of sensor failure or malfunction!

For this reason, the issue is quickly resolved by cleaning the sensor (and the amp).

Keep reading for the step-by-step process.

How to get rid of the problem

In truth, the Dyson air quality sensor problem 999 is largely eliminated by simply cleaning up the sensor.

Don’t believe us? Follow the steps below to clean the sensor and tell us (in the comments section at the end of the article) if it has worked for you..

Dyson air quality sensor problem – step by step cleaning procedure

Here are the complete Dyson pure cool troubleshooting steps for the irritating glitch…

Step 1: Locate the sensor

The typical Dyson pure cool sensor location is 0n the left of your LCD display.

Check there- you’ll notice two tiny sensor holes. You’re likely to find the sensor here for the most part.

Of course, the holes may be in a different location on some Dyson pure cool fan models.

For example, on TP04 units, the holes are found on the side. You will spot two slits above the filters (toward the back).

Step 2: Turn off the unit

Once you have found the holes, turn the power to the appliance off.

Step 3: Clean the sensor

There are a plethora of methods you can employ to clean the air quality sensor.

Choose the most convenient for you.

Option 1: Use a dusting brush (dry) to dust it

Brushes perform a slew of cleaning tasks and a dry brush can be useful for the procedure.

You simply need to brush the holes out (push the brush inside the openings as you clean).

An appropriately sized brush should eliminate any dust and help fix the fault instantly.

Option 2: Use a vacuum with the correct attachment to remove any debris

Another practical option would be to vacuum the debris out of the holes while its power is still turned off.

Be sure to vacuum the whole inside area out.

Quick Tip: Consider using any HEPA grade vacuum to ensure dust particles are completely captured and not re-introduced into the interior. Remember to select a correctly-sized attachment for the vacuum to work smoothly.

Option 3: Use compressed air to clean the inside

As an alternative, you can choose to blow out the two sensor holes – blowing with high pressure quickly cleans up any mess and the crucial accessory should start to function correctly again.

Quick Tip: A blow dryer works well too (on cool setting).

Step 4: Power the appliance back on

Put it back on and allow it to run normally.

If you have done it right, the severity reading should immediately come down from 999 to an accurate value.

Voila!

 

Troubleshooting Dyson problem with air quality sensor- Useful tips

If the fix has not worked as yet, the following tips could be handy:

·         Clean the filter as well

There are instances where cleaning the filter is necessary in order to get rid of the problem. Remove the filter then proceed to vacuum it clear.

Reinstall it and check if the sensor has started working.

·         Try to blow really hard

If the problem is still bothering you, it could be because you did not clean it properly.

Try to turn it off again and blow really hard on the slits with a can of compressed air.

This approach tends to be more effective than cleaning with a brush since any debris that might be stuck inside is easily dislodged.

Perform a hard reset

If still this doesn’t work, try to perform a hard reset on the unit then blow into the two sensor nostrils.

The hard reset is performed as follows:

• Pull out the machine’s power cord.
• Re-insert the power cord whilst holding the power button down on the machine.
• Wait until the display screen starts to flash then release the power button.

 

Dyson fan air quality sensor problem troubleshooting– frequently asked questions

What models does this solution work for?

This solution works for most Dyson units including Dyson Pure Cool Tower TP04 & DP04, Dyson DP05, Dyson Pure Cool tower, and more.

Why is Dyson air quality very poor on the Dyson app but good in home app?

If your machine keeps on reporting air quality as very poor on the Dyson app but good in the home app, it could be a programming issue.

Take a look at the logs – you want to check what the value of vact is.

If it is “fail”, clean the fan (both the sensor and filter) and see if it corrects the situation.

Recap

The most straightforward way to eliminate the Dyson fan air quality sensor problem is by simply vacuuming the sensor holes (on the side) and the amp.

This maintains proper sensor accuracy and makes sure the purifier continues to perform optimally.

But if everything fails – including the different cleaning methods- it could be time to contact Dyson support.
Here are the numbers to call:

• US: 866-693-9766
• CA: 1-877-397-6622
• UK: 0800-298-0298
• NZ: 0800 397 667
• AU: 1800 239 766

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