Lennox Hvac Error Code 133

The iComfort thermostat has found a problem with the air-handler outdoor sensor.

First step from the service manual

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

• 101The air-handler has lost communication with the rest of the…
• 102There is a frequency/distortion problem with the power to…
• 103The 24VAC to the air-handler control is lower than the…
• 104There is a delay in the air-handler responding to the…
• 105The iComfort thermostat has lost communication with the…
• 106There is a hardware problem with the air-handler control.
• 130An air-handler configuration jumper is missing.
• 131The air-handler control parameters are corrupted.