York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace TB Error Fix: Transformer Failure

The furnace transformer has failed, causing loss of 24V control voltage needed for ignition and blower operation. This fault results in furnace failure to start.

High severity2 fixes available

Quick Answer

Error TB on the York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace means: Transformer Failure. The top-ranked community fix is “Replace Transformer” (medium difficulty, ~30 min, DIY cost: $40-$60). 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

Electrical FaultPrimary

Electrical Fault → Wiring Harness Damaged

When to Call a Professional

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

This is a high severity error — continued use may cause damage or a safety hazard
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: $120-$180.

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

Filter Fault

2 fixes

Flame Lockout

2 fixes

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

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

Error code TB on the York TM9V100C20MP11 100,000 BTU 96% AFUE 2-Stage Variable-Speed Gas Furnace means: Transformer Failure. The furnace transformer has failed, causing loss of 24V control voltage needed for ignition and blower operation. This fault results in furnace failure to start.

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

The most successful fix is "Replace Transformer" (medium difficulty, ~30 minutes). Estimated DIY cost: $40-$60. HomeMD has 2 community-ranked fixes for this error.

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

This error is rated high severity. You should address it promptly — continued use could cause damage or safety concerns.

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

Yes — the top-ranked community fix ("Replace Transformer") is rated medium difficulty and takes about 30 minutes. Tools needed: Phillips screwdriver, Multimeter.

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

DIY cost: $40-$60. Professional repair typically costs $120-$180. 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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