Error code reference
Lennox Air Conditioner Error Code E601
Outdoor unit has been cycled OFF on low temperature protection
Outdoor unit has been cycled OFF on low temperature protection — outdoor temperature at or below -4°F (-20°C).
First step from the service manual
Outdoor unit will not operate when outdoor temperature is at or below -4°F. Unit continues operating until thermostat is satisfied or temperature drops to -15°F.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
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Get the full diagnostic procedure for E601.
- Step-by-step tests with expected resistance, voltage, and continuity values
- Wiring diagram references and connector pinouts from the OEM service manual
- Verified part numbers when replacement is required
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