Fisher & Paykel Dishwasher Error Code F40

When a Fisher & Paykel dishwasher flashes Error Code F40, it’s flagging a water-flow problem. In plain terms, the control isn’t seeing the fill and circulation it expects, so it pauses to protect the machine. The good news: most F40 cases come down to something simple—restricted water supply, a kinked hose, or a sticky inlet valve—and you can rule those out quickly and safely.

What F40 Actually Means

F40 is a water flow error. During fill or early wash, the dishwasher monitors how fast water enters and how the system reacts. If the flow is too low, inconsistent, or blocked, the control throws F40. That doesn’t automatically mean a failed part; it often means water isn’t getting to where it needs to go at the right rate.

You might notice the cycle starting and stopping, longer-than-usual fills, or spray arms that don’t sound like they’re hitting full speed. Sometimes the tub is barely wet when the code appears.

Likely Reasons Behind F40

There are a handful of usual suspects. At the tap, a partially closed shutoff or a clogged screen starves the dishwasher. Along the path, a kinked or crushed inlet hose slows flow. At the machine, the inlet valve may be stuck by mineral deposits, or the fine mesh filter on the valve could be packed with grit. Less commonly, low household water pressure or a circulation issue (debris lodged in the sump) can also trigger F40.

Safe, Smart First Steps (No Special Tools)

Before you begin, switch the dishwasher off at the breaker or unplug it. You’ll only restore power once each check is complete.

1. Power reset
   Leave it powered off for 5–10 minutes, then power back on and try a normal cycle. If F40 returns in the same spot, continue.
2. Open the sink hot-water tap fully
   Confirm strong, steady flow. If the tap sputters or is weak, address household supply or the shutoff valve first.
3. Check the dishwasher’s shutoff and hose routing
   Under the sink, make sure the water shutoff valve is fully open. Follow the inlet hose with your hand—no sharp bends, no kinks, nothing pinched behind bins or cleaning bottles. Straighten any tight curves.
4. Clean the inlet screens
   Turn off the shutoff valve. Disconnect the inlet hose from the valve on the dishwasher. Look for a small mesh screen in the hose fitting and/or in the valve body. Rinse sediment away and reattach firmly. Restore water and check for leaks.
5. Listen during fill
   Start a cycle and listen: you should hear a clean fill followed by confident spray. If fill sounds weak or the code returns quickly, the inlet valve may be sticking and need replacement.

If your model is a DishDrawer™, perform the same checks for each drawer’s inlet path and be sure nothing is pressing against the hoses behind the drawers when they close.

When DIY Isn’t Enough

If F40 reappears after a reset and basic checks, the machine may need a new inlet valve, a deeper cleaning of the sump and filters, or evaluation of water pressure to the unit. Internal circulation issues (blockage in the sump, failing circulation pump, or a float sensor not reading correctly) can mimic low flow and should be inspected with the tub panels removed. At that point, a professional diagnosis is the fastest way to protect the electronics and get reliable wash performance back.

Simple Habits That Prevent F40

A few maintenance habits go a long way toward keeping water-flow faults away:

• Keep the under-sink shutoff fully open and cycle it a couple of times a year so it doesn’t seize in a half-closed position.
• Avoid tight hose bends when organizing under-sink storage; give the inlet hose a clean path with gentle curves.
• Every few months, pull out and rinse the main filters inside the tub. Don’t let seeds, glass chips, or pasta fragments pile up in the sump.
• In hard-water areas, run a descaling/cleaner cycle periodically to reduce mineral buildup on the inlet valve and spray systems.
• Start cycles with hot water at the sink already running for a few seconds; a hot start shortens heat-up and helps the machine read healthy flow/temperature changes.

Quick Recap

F40 means the dishwasher isn’t getting the water flow it expects. Start with a power reset, verify strong household hot water, check that the shutoff is fully open, straighten the inlet hose, and clean the inlet screens. If the error returns, the inlet valve or internal circulation may need service. Handle those basics and your Fisher & Paykel should be back to steady, quiet cleaning—without code interruptions.