This code indicates the lower spray arm isn’t operating as the control expects. The machine monitors feedback from the lower wash system; when the arm can’t rotate or the drive circuit doesn’t respond correctly, the control flags 9–4 (F9E4) and cleaning performance drops.
Why the Lower Spray Arm Matters
The lower arm delivers the highest-volume wash action. If it slows, stalls, or never starts, soils remain on the bottom rack, tall items don’t rinse, and overall coverage suffers. Correcting the fault restores pressure, rotation, and even spray patterns across the entire tub.
How the Problem Usually Shows Up
You’ll notice gritty residue on plates, a heavy film on pans, or tall glasses that come out spotty. The cycle may sound quieter than normal because water isn’t jetting through a spinning arm. Sometimes the code appears after you load a large pan or utensil that physically blocks rotation; other times it returns every cycle, which points to a mechanical or electrical issue in the drive path.
Common Root Causes
Physical obstructions are the most frequent culprit. Seeds, pasta, glass shards, or a low-hanging utensil can jam the arm or scrape its tips so it never reaches speed. Mineral scale or fat residue can glue the arm to its bearing and add drag. When mechanics check out, attention shifts to the drive: a loose or oxidized connector at the lower spray arm motor cuts power intermittently, a fatigued harness opens under vibration, or the motor itself loses torque with heat and age.
Safety First
Shut off power at the breaker or unplug the dishwasher before you open panels or remove parts. Powering down protects you and prevents the control from logging new faults while you inspect.
Mechanical Checks That Solve Most Cases
Open the tub and spin the lower arm by hand. It should turn freely and coast a little; any scrape, wobble, or immediate stop means debris or wear. Lift the arm off its hub and rinse it under a tap to flush grit from the internal channels. Inspect the bearing surface and the hub for nicks, scale, or wrapped fibers. Re-seat the arm fully so the jets align with the designed thrust angles; a half-seated arm will spray but won’t develop rotation. While you’re there, verify nothing in the rack hangs into the arm’s path and that tall pans sit to the side rather than over the arm.
Electrical Path and Motor Health
With power still off, remove the toe-kick or lower access panel and follow the wiring to the lower spray arm motor. Confirm each connector locks firmly and the terminals look bright, not green or white with oxidation. Check the harness where it bends around brackets; a sharp edge can notch insulation and break a conductor inside. If you’re comfortable with a multimeter, verify continuity from the motor leads back to the control and gently flex the harness while testing to expose intermittent opens. A motor that spins when cold but faults after ten minutes often points to internal wear or thermal weakness.
Reassembly and Test
Restore power and run a short cycle. Listen for a healthy “whoosh-whoosh” as the lower arm comes up to speed and alternates pressure with the upper system (design-dependent). Open the door briefly mid-wash after the spray stops to avoid splashing, and confirm the arm moved to a new position. End the cycle and check several items on the bottom rack; they should rinse clean with no gritty film.
When Replacement Makes Sense
If the arm still binds after a thorough clean and proper seating, replace the arm and hub as a matched set to eliminate bearing wear and warped plastics. If the arm spins freely by hand but the error returns and electrical checks show solid continuity, replace the lower spray arm motor. Persistent faults after a known-good motor and harness merit a control-level evaluation, but that scenario is far less common than obstruction, wear, or a weak motor.
Keep the Code from Coming Back
Rinse heavy seeds and bones into the trash rather than the tub, load tall pans away from the arm’s sweep, and clean the filter screen on schedule so grit doesn’t recirculate into the hub. If you have hard water, run a monthly dishwasher cleaner to dissolve scale that stiffens bearings and clogs nozzles. These simple habits preserve rotation speed and keep 9–4 (F9E4) out of your cycles.