Frigidaire Dishwasher i20 Error: 6 Fixes for a Blocked Drain

Your Frigidaire dishwasher stopped part way through, the display reads i20, and there is an inch of grey water sitting over the filter. Nothing is broken yet. On most Frigidaire models built in the last ten years or so, i20 means one thing: the machine tried to pump the tub out, and the water was still there when the control checked.

One question splits the job in half. Has this dishwasher ever drained properly in this kitchen? If it is new, or if somebody replaced the garbage disposal or the sink plumbing recently, the odds sit heavily on an installation mistake and section 2 is where to start. If it drained fine for years and then quit, it is a clog, and almost all of those start at the filter. If your machine shows no code and just sits full of water, the general guide to a dishwasher that will not drain covers models without a display.

Start With These 30-Second Checks

1. 1Read the exact code, then look at the floor and the toe kick before you run anything. i20 is a drain fault, but i30 means water has already reached the pan under the machine, and water on the floor or a soaked cabinet base means stop: switch the dishwasher off at the breaker and dry it out first, because a forced drain pushes more water out of wherever it is escaping.
2. 2Run the garbage disposal for ten seconds with cold water, then watch the sink. A slow sink means the dishwasher has nowhere to send its water either.
3. 3Press and hold Start or Cancel for about three seconds. On most models that triggers a 90 second forced drain. A pump humming without moving water sounds nothing like a pump that stays silent.
4. 4Look at the drain hose in the sink cabinet. A kink, a crush point, or a hose lying flat on the cabinet floor are all findings.
5. 5If the dishwasher, disposal or sink plumbing was installed or swapped recently, skip straight to section 2.

1. Clean the Filter and Glass Trap

On a machine that drained fine until recently, this is the cause four times out of five. Fat and starch cement themselves into the fine mesh until the pump cannot pull water through fast enough.

1. 1Switch the dishwasher off at the circuit breaker. Many Frigidaire installs are hardwired into a junction box under the sink, so the control panel is not a disconnect.
2. 2Pull the lower rack out. Touch the water with the back of a gloved finger first, and if it is hot, leave the door open until it is not. Scoop the water into a bucket with a plastic cup, then sponge the last half inch out.
3. 3Twist the cylindrical fine filter counterclockwise about a quarter turn until it releases, then lift it straight out.
4. 4Press down on the center of the lower spray arm and turn the glass trap handle a quarter turn to unlock it. It moves under light pressure; if it will not, check your model's guide rather than forcing it, because the direction differs between model years.
5. 5Rinse both parts under a hot tap and brush the mesh through. Hold the fine filter up to a light: no daylight through it means it is not clean yet.
6. 6Wipe the sump with a gloved hand, feeling for glass and fruit pits. Refit the trap and filter, close the door, then restore power at the breaker with your hands clear and run a rinse cycle.

2. Knock the Plug Out of the Garbage Disposal

Every new garbage disposal leaves the factory with a molded plug sealing the dishwasher inlet on the side of the housing, so a disposal fitted in a kitchen without a dishwasher does not leak. Whoever installs it is supposed to knock that plug out, and it gets missed constantly. That is why it sits at the top of Frigidaire's own i20 checklist rather than the bottom. The symptom is exact: a machine that fills and washes normally and cannot push out a drop, either brand new or fine until the day the disposal was replaced. Note too that a disposal humming without turning is jammed solid, and nothing drains through it until that is freed.

1. 1Switch off the breakers for both the dishwasher and the disposal, then flip the disposal's wall switch to confirm nothing runs.
2. 2Put a bucket underneath. Loosen the clamp where the dishwasher drain hose meets the inlet nipple on the side of the disposal and pull the hose off. Expect a cup of dirty water.
3. 3Shine a flashlight into the inlet. An untouched plug looks like a flat disc set about half an inch inside the nipple. A clear view into the chamber means it is already gone.
4. 4If it is there, hold a flat blade screwdriver against it and tap the handle once or twice with a hammer. It drops into the grinding chamber.
5. 5Retrieve the disc with long needle nose pliers, never with fingers. Left inside, it jams under the grinding plate later.
6. 6Refit the hose, tighten the clamp, restore both breakers with your hands clear of the sink, and run a short cycle.

3. Straighten the Drain Hose and Raise the High Loop

Frigidaire asks for a high loop that rises to the underside of the countertop before the hose drops to the disposal or standpipe; installation sheets usually put the minimum at about 20 inches above the floor. That loop stops dirty sink water siphoning back into the tub after every drain, and a hose lying flat across the cabinet floor is a common shortcut.

1. 1Switch off the breakers for both the dishwasher and the disposal before you move the machine or open any connection. The two are usually on separate circuits, and the steps below open a joint right at the disposal.
2. 2Follow the hose and look for a kink at the cabinet wall, a flattened section where the machine was pushed back, or a run with no rise in it. Measure the highest point of the hose from the floor. If it never rises much above the connection, strap it up against the underside of the countertop with a bracket or clamp.
3. 3Bail the standing water out of the tub with a cup and a bucket before you open anything. A hose with no high loop empties the whole tub into the cabinet the moment you pull it off the disposal.
4. 4With a bucket and old towels under the joint, pull the hose off at the disposal end and run water through from a tap. A hose that will not pass water freely holds a grease plug, usually within a foot of that end.
5. 5Clear it with string trimmer line from the disposal end and flush again. Replace the hose if the inner wall has collapsed; a universal one runs about $20 to $40.
6. 6Reconnect both ends, tighten the clamps, restore power at the breaker with your hands clear, and run a rinse cycle while watching for drips.

4. Clear the Air Gap on the Countertop

Not every kitchen has one, but if a small chrome cylinder pokes up beside the faucet, that is the air gap. Cooked starch and eggshell build up inside until nothing gets past.

1. 1Switch the dishwasher off at the breaker so nobody starts a cycle while the cap is off. A draining machine sprays dirty water out of an open air gap.
2. 2Twist the chrome cover off, then unscrew the plastic cap underneath by hand.
3. 3Pull the debris out of both ports with pliers or a bottle brush. The short hose from the air gap down to the disposal blocks just as often, so squeeze along it too.
4. 4Refit the cap and cover, restore power at the breaker with your hands clear of the air gap, and run a rinse cycle. Water spitting out of the air gap during the drain means the hose below is still blocked.

5. Free the Check Valve in the Sump

At the mouth of the drain port, under the filter, sits a small flap or ball that lets water out and stops it running back. Debris holds it open, a stuck valve blocks the outlet, and either way the tub stays full.

1. 1Switch off at the breaker, open the door and let a hot tub cool for 30 minutes, bail the standing water out with a cup, then remove the fine filter and glass trap as in section 1.
2. 2With a work glove on, find the flap or ball in the drain port. It should swing or roll freely under a gloved fingertip and settle back.
3. 3Pull out whatever is caught around it. Toothpicks, fruit stickers, twist ties and glass shards are the usual four.
4. 4Refit the trap and filter, close the door, restore power at the breaker with your hands clear, and run a rinse cycle.

6. Test the Drain Pump

With everything upstream clear, the pump is the last mechanical suspect. Humming without moving water means jammed or a failed impeller. Silence during the forced drain means dead, or getting no power.

1. 1Switch off at the breaker, confirm the panel stays dark with the door open, then close the water supply valve under the sink and disconnect the supply line and drain hose into a bucket.
2. 2Bail every drop of standing water out of the tub with a cup and a sponge before you move the machine. Tipping a full tub onto its back empties it over the floor and into the control area.
3. 3Undo the brackets holding the machine to the underside of the countertop or the cabinet sides, tape the door shut, and slide the machine out. With a helper taking the weight, lay it on its back on an old towel, then remove the lower access panel to expose the pump.
4. 4Turn the impeller by hand. It should spin freely. Gritty or locked usually means glass or a bone fragment behind the blades, and clearing that is the whole repair.
5. 5Unplug the pump connector and measure across its terminals with a multimeter on ohms. Most Frigidaire drain pump windings land between 15 and 40 ohms, but check the tech sheet behind the kick panel for your model's figure before condemning the part.
6. 6Fit the replacement, reconnect supply and drain, push the machine back, screw the brackets back in, reopen the water supply valve, restore power with your hands clear, and run a rinse cycle. The part runs about $20 to $100.

Tools You Will Probably Need

When to Call a Pro

If the filter is clean, the plug is out, the hose is clear and looped, the air gap is open and the pump spins and reads in range, what is left is electrical: the harness to the pump, the level sensing, or the control board.

1. 1Ask for the diagnostic fee up front. A service call minimum generally runs $70 to $130 and covers the first hour.
2. 2Check the warranty first. Most Frigidaire dishwashers carry a one year parts and labor warranty, and the paperwork or the model page confirms what yours has.
3. 3If the machine is over eight years old and the quote passes about $300, weigh it against a new entry level dishwasher at $400 to $600.
4. 4Tell the technician what you ruled out: filter, disposal plug, drain hose, air gap, pump resistance. It saves the first half hour of the visit.
5. 5If water has appeared in the pan under the machine and the code switched to i30, say so when you book. The pan has to be dried out before the machine runs at all.