Fisher & Paykel Dishwasher Error Code F85

The F85 error code on a Fisher & Paykel dishwasher indicates a bridge temperature sensor fault originating within the motor controller. The motor controller contains an internal temperature sensor, often referred to as a bridge or H-bridge sensor, that monitors the thermal state of the controller's power switching components. These components manage the motor's drive circuitry, and the sensor exists to protect them from overheating during operation. When the controller's internal diagnostics detect an anomalous reading from this sensor, whether it falls outside expected parameters or becomes unresponsive, the F85 fault is triggered and the dishwasher halts operation.

Because the bridge temperature sensor is integrated into the motor controller assembly itself, it is not a separately serviceable component. The sensor circuit, its reference values, and the logic that interprets its readings are all part of the controller board. This means that diagnosing whether the fault stems from a true thermal event, a failed sensor, or degraded signal circuitry on the board is not practical through external testing alone. The controller must be treated as a single unit for diagnostic and replacement purposes.

The primary and recommended diagnostic action for F85 is direct replacement of the motor controller. Attempting to continue running the dishwasher with this fault active risks operating the motor drive components without valid thermal protection, which could lead to further damage. A technician should confirm the error code is stable and not intermittent before proceeding with controller replacement, as an intermittent fault could point to a loose electrical connection at the controller harness rather than internal component failure.