Error code reference

Carrier Hvac Error Code 44

Motor communication fault

Motor communication fault — fan coil control cannot communicate with the ECM blower motor.

First step from the service manual

Check the motor wiring harness for proper connection to control and motor receptacles; check harness wiring complies with wiring diagram and is not shorted.

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

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Step-by-step tests with expected resistance, voltage, and continuity values
Wiring diagram references and connector pinouts from the OEM service manual
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Motor communication fault — fan coil control

From Service Manual 761144, p.36:

1.Check the motor wiring harness for proper connection to control and motor receptacles; check harness wiring complies with wiring diagram and is not shorted.

2.Inspect the communication harness between the main control and the UI board for bent pins or unseated connectors at each end.

3.Measure supply voltage to the UI board. Expected: 5 VDC at the interface connector; a low or missing rail points back to the main control supply.

Part W10811169

User interface control board

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First step from the service manual

Get the full diagnostic procedure for 44.

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