Written by
Appliance Care Desk Appliance Care EditorPublished September 2, 2026Updated October 17, 2026
Content status:
Verified
Error codeU4
ApplianceDishDrawer Dishwasher
Quick answer
U4 points away from itself: the fault sits in the neighbouring drawer.
Model compatibility: Fisher & Paykel reuses codes across series and model years, so U4 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
U4 means a fault in the other drawer is stopping this drawer from running; the drawer showing U4 is fine.
U4 is a message about the neighbouring drawer, not about the one showing it. The manufacturer’s DishDrawer guide states that the drawer displaying U4 has no fault of its own. It is held back from running because something is wrong with the second drawer.
Where to look
Walk over to the second drawer and read its panel, plus the screen when your unit includes one. Look up whatever code it shows and deal with that. The Classic guide puts it briefly: attend to the fault code on the other drawer. After that fault is cleared, U4 should stop applying.
Can this drawer be used meanwhile?
Not really. According to the guide, U4 rules out using that drawer until its twin has been sorted out.
What the Classic flowchart says
Every U-code in the Classic chart begins with three moves: silence the beeper, locate the code in its table, and note it. For U4 the chart then says to ignore this drawer and deal with the second drawer’s code. Only when the fault is still present afterwards does it tell you to disconnect both power and water, then contact Customer Care, quoting the code.
A worked illustration
Say the lower drawer reads U1 since its water tap was closed. The upper drawer may display U4 simultaneously. Turn the tap on and clear U1 (see the U1 page) and that is the entire remedy. Take this as a picture of how the rule works only; the guide never states which codes go together with U4.
No code on the other drawer
Nothing in the manufacturer’s material covers this case. A sensible move is to cut power to the unit at the supply, give it a few seconds, and turn it back on. If U4 comes back while the other drawer still shows nothing, mention exactly that when you call, since it does not fit the guide’s explanation.
Codes the other drawer might show
An E-code or F-code pointing at electronics: F9 covers the controller that runs the wash.
FC or EC: FC deals with the link between the two drawers.
For a Fisher & Paykel DishDrawer in Los Angeles, the DishDrawer repair page has the details, or you can ring (310) 872-1939. Have both drawers’ codes written down, one per drawer, and say which drawer was showing U4 when you noticed it.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your Fisher & Paykel appliance?
Book a specialist visit for a clear estimate and approval before any repair.
