Lennox HVAC Error Code E23: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
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Error Code
E23
Brand
Lennox
Product Type
hvac
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Error code E23 on a Lennox HVAC system indicates a fault with the indoor coil temperature sensor. This sensor monitors the temperature of the evaporator coil to ensure efficient operation and prevent freezing. When it fails, the system may stop cooling or run erratically. This guide helps you diagnose and fix the issue.
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Tools You'll Need

How to Fix Error Code E23

  1. Power Off the System

    Always shut off power before accessing electrical components.

  2. Locate the Indoor Coil Sensor

  3. Inspect Sensor Wiring and Connection

  4. Test the Sensor Resistance

    Handle the sensor carefully; it is fragile.

  5. Check Control Board for Damage

  6. Replace the Sensor (if faulty)

    Use only a compatible replacement sensor for your Lennox model.

  7. Restore Power and Test

Parts You May Need

Indoor Coil Temperature Sensor
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Indoor Coil Temperature Sensor
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Indoor Coil Temperature Sensor
Check Price on Amazon
Indoor Coil Temperature Sensor
Check Price on Amazon
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When to Call a Professional

If replacing the sensor does not clear the error, or if you suspect a faulty control board or wiring issue beyond simple repairs, call a licensed HVAC technician. Also, if you are uncomfortable working with electrical components, seek professional help.

Frequently Asked Questions

Can I bypass the indoor coil temperature sensor?
No, bypassing the sensor is not recommended. It can cause the system to freeze or operate inefficiently, leading to compressor damage. Always replace a faulty sensor.
Will error E23 cause my Lennox system to not cool at all?
Yes, the system may disable cooling to protect the compressor. You might see intermittent cooling or no cooling until the sensor is replaced.
How much does it cost to fix error E23?
If you DIY, the sensor costs $15-$40. Professional repair (including service call) typically ranges from $150-$300.
Is a bad indoor coil sensor a common issue in Lennox systems?
Yes, sensors can fail over time due to age, moisture, or electrical surges. It's a common HVAC issue across brands.
Can I clean the sensor instead of replacing it?
Cleaning is rarely effective. If the sensor is dirty, gently wipe it with a soft cloth, but if it fails the resistance test, replacement is necessary.

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