LG Dishwasher Wash Motor Not Starting: Causes

Two different starting systems#

LG splits into two designs, and the fix depends on which one you own:

• Inverter Direct Drive (roughly 2015 and newer, LDF and LDT series): there is no start capacitor. An inverter board ramps voltage and frequency electronically to spin the motor up, so a no-start here is the inverter board, the motor winding, or a jammed impeller.
• Older single-speed AC motor (pre-2015, such as the LD-2131SH): uses a start capacitor (often in the 6uF-10uF range) to create the phase shift that starts the motor. When it fails the motor hums but cannot turn, and the capacitor is a cheap, quick swap.

To tell them apart, check the model number and look under the tub: an inverter board is a distinct circuit board near the motor, while a capacitor is a small two-wire cylinder mounted on the frame or beside the motor.

Before you start#

• Tools: Phillips #2 screwdriver, Torx T15, a multimeter (with a capacitance range for older models), a flashlight, and towels.
• Safety: Disconnect power at the breaker and unplug the machine. Capacitors hold a charge after power is off — wait 5 minutes for them to bleed down, and if you must discharge one by hand, short its terminals with an insulated screwdriver and expect a spark.

Step by step#

1. Rule out an impeller jam. Pull the racks and filter, twist off the lower spray arm (it is reverse-threaded), and look into the pump intake. Try to spin the impeller by hand; glass, bone, or a stuck label will stall the motor on startup and trip LE, and clearing it often fixes the fault with no electrical work at all.
2. Reseat the motor connector. With power off, drop the lower access panel (4 Phillips screws), find the multi-pin motor connector at the tub base, and push it firmly home. Look for corrosion, bent pins, or melted plastic — a poor connection starves the motor of current and causes intermittent LE.
3. Test the motor winding. Unplug the motor connector and, on ohms, measure across the winding pins. On a three-phase IDD motor all three pairs should read similar resistance (roughly 5-30 ohms). An open (OL) reading is a dead winding, a near-zero reading is a short, and wildly uneven pairs mean the motor is on its way out.
4. Test the start capacitor (older models only). If your model has a separate capacitor, disconnect its leads, set the meter to capacitance, and read across the terminals — a good part sits within 10% of its printed value (a 6uF cap should land around 5.4-6.6uF). Much lower, or an open reading, means replace it with the same microfarad and voltage rating.
5. Inspect the inverter board (IDD models). The board lives near the motor, usually under the tub. Look for burnt or blackened power transistors, swollen board capacitors, cracked solder joints, or scorched traces — any visible damage means the board needs replacing.
6. Replace the failed part. For a capacitor, note the lead positions and swap it into the same bracket. For an inverter board, photograph every connector first, unbolt it, transfer the connectors exactly, and confirm each one is fully seated. If the winding itself is dead, the pump-motor assembly is the repair.
7. Reassemble and test. Refit the panels, restore power, and start a Normal cycle. The motor should engage within 30-60 seconds of filling, with the usual whoosh of spray, and you should let the cycle finish to confirm LE or nE does not return.
8. Monitor for two days. Start-up faults are often intermittent — a weak capacitor or a heat-sensitive board can work cold and fail warm. Run the machine daily for 48 hours; if the error shows only on long hot cycles, suspect a thermal failure in the inverter transistors or the winding.

Quick pattern guide#