Activated Charcoal Filter (ACF)

Back to: WIS 83.40 Automatic Climate Control (ACC) or Heating Ventilation and Air Conditioning (HVAC)

Description - Activated Charcoal Filter (ACF)

The Activated Charcoal Filter is constructed using activated carbon which is able to remove the odors, contaminants and impurities found in smog, using chemical absorption.

The W220 S Class has smog sensors which continually monitor the outside air quality and if high levels of contamination (NOx and CO) are detected, automatically operate the Activated Charcoal Filter and put the ACC in Recirculation Mode. Note the Activated Charcoal Filter is used in conjunction with the Cabin Ventilation Dust Filters which remove the particulate matter from the in-coming or re-circulated air.

The Activated Charcoal Filter can also be used manually.

Location - Activated Charcoal Filter (ACF)

• LHD vehicle below the right (passenger) instrument panel.
• RHD vehicle below the left (passenger)instrument panel.

Issues - Activated Charcoal Filter (ACF)

• The ACF becomes clogged with very fine dust (the main ACC dust filters should have removed most of the dust) and contaminated with fumes.
• The ACF requires regular servicing.

Service Interval - Activated Charcoal Filter (ACF)

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Parts - Activated Charcoal Filter (ACF)

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DIY - Activated Charcoal Filter (ACF)

DIY Tips - Activated Charcoal Filter (ACF)

• NOTE: Activated charcoal filters must not be cleaned but should always be replaced.
• The hardest part about getting out the charcoal filters was the dexterity required. Had to get under the dash. Removed a few screws on a flat plastic panel and then had to gently pull it out.
• There are overlapping plastic flaps that only come apart by gently manipulating.
• Once you get them off, there are two nifty plastic hinged doors that swing open and all you do is slide out filters, straight down towards the floor.

DIY Replacing - Activated Charcoal Filter (ACF)

• Undo One Phillips screw and two 8mm screws.
• Remove right cover below instrument panel. I didn’t have to remove knee protection (3) as it will bend out of the way to remove the canisters.
• Pull back right front floor covering
• Move locking slide (2) in the direction of the arrow and remove cover (1)
• Remove both activated charcoal filters (3) downwards out of the AC housing
• Install in the reverse order.

Refer to WIS AR68.10-P-1520M Removing and installing cover below instrument panel (right) 17.11.97