Coway airmega 400 reset filter light

The letters on the [Max2 Change] button are lit. The Max2 filters need replacing. On the 400S and 400 the button also shows the filter life in levels from 100% down to 0%.

Cause 1 of 2The Max2 filter life has run out, about 12 months at 8 hours a day at maximum speed. Real life depends on running time and fan speed. Source: Checking the product; Filter Maintenance and Cleaning Parts; How to replace the Max2 Filter, pp. 10, 19, 21

First checkReplace the Max2 filters on both sides.

Causes and checks

The Max2 filter life has run out, about 12 months at 8 hours a day at maximum speed. Real life depends on running time and fan speed. Source: Checking the product; Filter Maintenance and Cleaning Parts; How to replace the Max2 Filter, pp. 10, 19, 21
1. Replace the Max2 filters on both sides. See Replace the Max2 filters.
2. Touch and hold the [Max2 Change] button for 2 to 3 seconds to reset the indicator.
The replacement cycle was not reset after replacing the Max2 filters. Source: How to replace the Max2 Filter, p. 21
1. Touch and hold the [Max2 Change] button on the control panel to reset the indicator. The replacement cycle must be reset after every filter change.

Service

If the checks above do not clear it, contact Coway customer service: 1-800-285-0982, cowaymega.com. United States (warranty service, 8:00 am to 5:00 pm PT, Monday to Friday). Source: Limited Warranty, p. 28

Other Airmega 400 indicators

[Pre Wash] indicator: The pre-filters need cleaning. On the 400S and 400 the button also shows the pre-filter cleaning cycle in levels from 100% down to 0%.
Wi-Fi indicator: Wi-Fi connection state of the Airmega 400S and 300S.
Air quality indicator colour: Pollution level around the purifier. 400S and 300S: blue and green is Good, green and yellow Moderate, yellow and pink Unhealthy, pink and red Very Unhealthy. 400 and 300: blue is Good, purple Moderate, pink Unhealthy, red Very Unhealthy.

Sources

User Manual, Air Purifier 400S/400/300S/300 (English, French). Coway. Document 1216776, revision 003, 88 pages, en-US. cowaymega.com. Listed on the manufacturer's support page. Retrieved 13 November 2026.

Page numbers are the numbers printed in the manual. Where this page and the manual differ, follow the manual.

Applies to: AP-2015E (variant AP-2015E(SILVER_US)), AP-2015F (variant AP-2015F(SILVER_US)), AP-1515G, AP-1515H. United States.
Source: User Manual, Air Purifier 400S/400/300S/300 (English, French), 1216776 revision 003
Last verified: 13 November 2026
Handbook: Coway Airmega 400S, 400, 300S and 300 air purifiers in Air purifiers; all Coway handbooks