AO
LG Dishwasher
Severity: ModerateWhat Does This Error Mean?
The AO error on an LG dishwasher indicates a problem with the diverter motor or the diverter valve assembly. The diverter motor controls which spray arm gets water during the wash cycle. When it fails, water may not reach all areas of the dishwasher and dishes come out dirty.
Affected Models
- LDP6797ST
- LDFN4542D
- LDT5678SS
- LDTS5552S
- Most LG dishwashers with multi-zone spray systems
Common Causes
- The diverter motor has burned out and can no longer redirect water between spray zones
- A piece of broken dish, food debris, or label sticker is jamming the diverter valve
- The wiring harness to the diverter motor has come loose or corroded
- The diverter valve assembly itself is cracked or warped from heat
- The main control board has failed and is not sending signals to the diverter motor
How to Fix It
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Cancel the current cycle and open the dishwasher door.
Press Cancel or the Start button for 3 seconds to stop the cycle safely.
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Remove the lower dish rack and check the bottom of the dishwasher tub.
Look for broken glass, food particles, or debris that could be lodged in the diverter area near the spray arm.
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Remove the lower spray arm by unscrewing or unclipping it and rinse it under the sink.
Check the spray arm holes for blockages — use a toothpick to clear any clogged holes.
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Run the dishwasher's rinse-only cycle to flush out any remaining debris.
This can sometimes dislodge small particles from the diverter area.
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If the AO error returns after the rinse cycle, the diverter motor needs professional inspection.
Do not keep running full cycles — water may not be reaching all dish zones, leaving dishes dirty and wet.
When to Call a Professional
If clearing debris and resetting the dishwasher does not resolve the AO error, call a technician. The diverter motor or diverter valve assembly will need inspection and likely replacement. This repair requires partially disassembling the dishwasher sump area. Expect repair costs of $120–$260 depending on parts and labor in your area.
Frequently Asked Questions
Will my dishes still get clean with the AO error showing?
Probably not — the diverter motor controls which spray zones get water. If it is faulty, only part of the dishwasher may be getting washed. Dishes in the affected zone will come out dirty or not fully rinsed.
What is a diverter motor and what does it do?
Think of the diverter motor as a traffic director for water inside your dishwasher. Instead of spraying all zones at once, LG dishwashers rotate water pressure between the upper rack, lower rack, and the bottom spray zone. The diverter motor switches water flow between these areas during the wash cycle. This uses water more efficiently and increases washing pressure in each zone.
How much does it cost to fix the AO error on an LG dishwasher?
The diverter motor assembly typically costs $40–$90 as a part. With a technician's labor, the total repair is usually $130–$260. Some technicians may recommend replacing the entire sump assembly if the diverter and drain motor are combined in one unit. Get a quote before authorizing any repair.