What F42 Means
WHICH MACHINES THIS APPLIES TO: F42, printed on the DW90.1 display as F:42, is a DW90 platform code. It is not in the DW20 or DW70 tables, where the thermistor fault is F3, and it is not among the codes the current DBI, DFI and DSD user manuals publish.
DW90 PLATFORM - WHAT F42 MEANS: the service manual reads "Thermistor fault. Communication between the thermistor and control unit has stopped or the thermistor is reporting temperatures greater than 80 degrees Celsius. Program continues with the process. Only indicated in service menu." The check list is "Thermistor, plugs, wire harness, and control unit."
WHAT THE MACHINE DOES NEXT: it carries on with the programme. The owner sees nothing, because the manual places the indication in the service menu only. The symptom that does reach the owner is a wash that never gets properly hot and a drying result that has quietly declined.
A NOTE ON WHAT YOU MAY READ ELSEWHERE: some parts retailers list F42 as a communication error. That is a loose paraphrase of Asko's own phrase "communication between the thermistor and control unit has stopped" - it is the same fault described sloppily, not a different one. The fault is in the temperature sensing circuit.
CLASSIFICATION: fault. Nothing stops and nothing is at risk, but the machine has lost the reading it needs to heat correctly.
Common Causes of F42
- Thermistor failed or out of range
- Plug or connector at the thermistor loose or corroded
- Wire harness damaged between the sensor and the control unit
- Control unit not reading an otherwise sound sensor
🔧 One Safe Check You Can Try
There is no display message and no owner check, so the value here is in observing well. Run a hot programme and feel the door and the load at the end - a machine with a broken temperature circuit usually finishes barely warm. Note whether the problem is constant or comes and goes, because an intermittent loss of signal usually means a plug or a section of harness rather than the sensor itself, and that distinction saves a technician a lot of time. Take the model number from the plate on the inside edge of the door while you are there. Do not go looking for the sensor: on the DW90 it sits at the sump under the wash tub, its harness runs beside the pump supply, and reaching any of it means isolating the machine at the outlet or the breaker and drawing a built-in appliance out of the cabinet with its plumbing still attached.
⚠ Why You Shouldn't Go Further Than That
- The thermistor is mounted at the sump beneath the wash tub, reachable only with the appliance isolated from power and drawn out of the cabinet.
- Its harness runs with the pump and element wiring in the base, which carries mains voltage whenever the machine is connected.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.