❄️Air Conditioner

York · YZF42B21S LX Series AC

York YZF42B21S LX Series AC E1 Error Fix: Indoor Temperature Sensor Failure

The indoor temperature sensor is not providing a valid reading. This could be due to a sensor malfunction or wiring issues. The AC may run inefficiently or fail to maintain the desired temperature.

Medium severity2 fixes available

Quick Answer

Error E1 on the York YZF42B21S LX Series AC means: Indoor Temperature Sensor Failure. The top-ranked community fix is “Replace Indoor Temperature Sensor” (medium difficulty, ~30 min, DIY cost: $20-$35). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · air conditioner

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

Sensor MalfunctionPrimary

When to Call a Professional

While many air conditioner 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: $120-$180.

Other York Models with Error E1

DERA-F036N07 14 SEER

air_conditioner · 2 fixes

YHG42B21S 3.5 Ton 14 SEER 10 HSPF Affinity Series Heat Pump with Variable-Speed Compressor

heat_pump · 2 fixes

YZH36B21S 3 Ton 16 SEER 9.5 HSPF Heat Pump with Environmentally Friendly Refrigerant

heat_pump · 2 fixes

Other York YZF42B21S LX Series AC Error Codes

Outdoor Coil Temperature Sensor Fault

2 fixes

High Pressure Switch Trip

2 fixes

Low Pressure Switch Trip

2 fixes

Compressor Overcurrent Protection

2 fixes

Indoor Fan Motor Locked Rotor

2 fixes

Outdoor Fan Motor Locked Rotor

2 fixes

Indoor Coil Freeze Protection Activated

2 fixes

Drain Pump Failure

2 fixes

People Also Ask About York YZF42B21S LX Series AC Error E1

What does error code E1 mean on a York YZF42B21S LX Series AC?

Error code E1 on the York YZF42B21S LX Series AC means: Indoor Temperature Sensor Failure. The indoor temperature sensor is not providing a valid reading. This could be due to a sensor malfunction or wiring issues. The AC may run inefficiently or fail to maintain the desired temperature.

How do I fix error code E1 on my York YZF42B21S LX Series AC?

The most successful fix is "Replace Indoor Temperature Sensor" (medium difficulty, ~30 minutes). Estimated DIY cost: $20-$35. HomeMD has 2 community-ranked fixes for this error.

Is error code E1 on a York YZF42B21S LX Series AC 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 YZF42B21S LX Series AC error E1 myself?

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

How much does it cost to repair York YZF42B21S LX Series AC error E1?

DIY cost: $20-$35. 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 YZF42B21S LX Series AC have?

The York YZF42B21S LX Series AC has 8 other known error codes, including: E2 (Outdoor Coil Temperature Sensor Fault), E3 (High Pressure Switch Trip), E4 (Low Pressure Switch Trip), E5 (Compressor Overcurrent Protection), E6 (Indoor Fan Motor Locked Rotor), and 3 more.

Which other York models have the E1 error?

Error code E1 also appears on 3 other York models: DERA-F036N07 14 SEER, YHG42B21S 3.5 Ton 14 SEER 10 HSPF Affinity Series Heat Pump with Variable-Speed Compressor, YZH36B21S 3 Ton 16 SEER 9.5 HSPF Heat Pump with Environmentally Friendly Refrigerant. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the York YZF42B21S LX Series AC have?

The York YZF42B21S LX Series AC has 8 other known error codes:

E2 — Outdoor Coil Temperature Sensor Fault (2 fixes)
E3 — High Pressure Switch Trip (2 fixes)
E4 — Low Pressure Switch Trip (2 fixes)
E5 — Compressor Overcurrent Protection (2 fixes)
E6 — Indoor Fan Motor Locked Rotor (2 fixes)
E7 — Outdoor Fan Motor Locked Rotor (2 fixes)
E8 — Indoor Coil Freeze Protection Activated (2 fixes)
E9 — Drain Pump Failure (2 fixes)

Which other York models have the E1 error?

Error code E1 also appears on 3 other York models:

DERA-F036N07 14 SEER (air conditioner) · 2 fixes
YHG42B21S 3.5 Ton 14 SEER 10 HSPF Affinity Series Heat Pump with Variable-Speed Compressor (heat pump) · 2 fixes
YZH36B21S 3 Ton 16 SEER 9.5 HSPF Heat Pump with Environmentally Friendly Refrigerant (heat pump) · 2 fixes

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