York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace FF Error Fix: Filter Fault

The furnace detected a clogged or dirty air filter causing reduced airflow. This error may trigger high temperature shutdowns or reduced heating efficiency.

Medium severity2 fixes available

Quick Answer

Error FF on the York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace means: Filter Fault. The top-ranked community fix is “Replace or Clean Air Filter” (easy difficulty, ~15 min, DIY cost: $10-$20). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · furnace

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

Root Cause Analysis

Mechanical Wear

When to Call a Professional

While many furnace repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $80-$120.

Other York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace Error Codes

Burner Blocked

2 fixes

Blower Fault

2 fixes

Control Board Failure

2 fixes

CF1

Circulation Fan Fault

2 fixes

Exhaust Blockage

2 fixes

Flame Detection Failure

2 fixes

Flame Lockout

2 fixes

Flame Sensor Shorted

2 fixes

People Also Ask About York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace Error FF

What does error code FF mean on a York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace?

Error code FF on the York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace means: Filter Fault. The furnace detected a clogged or dirty air filter causing reduced airflow. This error may trigger high temperature shutdowns or reduced heating efficiency.

How do I fix error code FF on my York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace?

The most successful fix is "Replace or Clean Air Filter" (easy difficulty, ~15 minutes). Estimated DIY cost: $10-$20. HomeMD has 2 community-ranked fixes for this error.

Is error code FF on a York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace serious?

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Can I fix York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace error FF myself?

Yes — the top-ranked community fix ("Replace or Clean Air Filter") is rated easy difficulty and takes about 15 minutes. Tools needed: None.

How much does it cost to repair York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace error FF?

DIY cost: $10-$20. Professional repair typically costs $80-$120. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace have?

The York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace has 8 other known error codes, including: BB (Burner Blocked), BF (Blower Fault), CF (Control Board Failure), CF1 (Circulation Fan Fault), EB (Exhaust Blockage), and 3 more.

What other error codes does the York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace have?

The York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace has 8 other known error codes:

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