Kenmore Washer F25: Drive Motor Tachometer Signal Lost

What You Are Experiencing

Your Kenmore washer began a cycle — likely agitation or spin — and stopped abruptly with F25 on the display. The drum may have been moving slowly or not at all when the code appeared. In some cases, you hear the motor humming as if trying to spin but the drum barely moves or oscillates weakly before the error trips.

F25 differs from a complete "no start" situation: the board DID attempt to run the motor. The motor MAY have started spinning. But the tachometer feedback signal — the speed sensor that reports RPM back to the control board — either disappeared during operation or never appeared at all.

Why This Happens

On Whirlpool-manufactured Kenmore washers (prefix 110.xxxxx), the motor control system is a closed feedback loop. The Motor Control Unit (MCU) sends power to the drive motor at a calculated frequency and voltage to achieve a target speed. Simultaneously, a tachometer mounted on the motor sends electrical pulses back to the MCU — each revolution generates a fixed number of pulses. The MCU counts these pulses to verify the motor actually reached the commanded speed.

F25 triggers when the MCU detects one of these conditions:

• Zero tachometer pulses while motor power is being applied (complete signal loss)
• Pulse frequency far below what the applied power level should produce (motor is stalled or barely turning)
• Erratic pulse pattern that does not correspond to smooth rotation (intermittent signal)

Kenmore model prefix matters: This applies to 110.xxxxx (Whirlpool-built). The code "F25" does not exist on LG-built 796.xxxxx models (they use "LE" for motor drive errors) or Frigidaire-built 417.xxxxx models (they use "E5x" series).

Systematic Diagnosis

Start With the Obvious: Mechanical Binding

Before testing any electrical components, verify the drum can spin freely by hand. Open the door (front-loaders may require a manual door release if locked — see your tech sheet). Reach in and rotate the drum. It should spin smoothly with moderate effort. If it is extremely difficult to turn, feels gritty, or will not rotate at all, the problem is mechanical — not electrical:

• Frozen bearing (grinding feel when turning = bearing race failure)
• Object wedged between drum and tub (bra wire, coin stuck between inner basket and outer tub)
• Seized transmission (top-loaders with gear transmission — won't turn in either direction)
• Broken spider arm (front-loaders — the three-arm mounting that connects drum to shaft)

If the drum spins freely by hand, proceed to electrical diagnosis.

The Tachometer Coil

The tachometer (also called rotor position sensor or RPS on direct-drive models) is a small electromagnetic sensor mounted directly on the motor assembly. On Whirlpool direct-drive top-loaders, it clips onto the stator at the bottom of the machine. On front-loaders, it is attached to the rear of the motor housing.

Access and test:

Unplug washer. For front-loaders: remove rear panel. For direct-drive top-loaders: lay machine on its front (protecting the floor and front panel), remove the base plate.

Locate the tachometer — a small circuit board or coil assembly with a wire connector (typically 3-5 pins). Disconnect its connector.

Resistance test: Set multimeter to ohms. Measure across the two tachometer coil pins (usually the outer two of a 3-pin connector — the center pin is often a ground or Hall power supply). Expected reading: 100-300 ohms (varies by motor model). An open reading (OL) means the coil wire inside the tachometer has broken — replace the tachometer assembly. A reading under 50 ohms suggests the coil is partially shorted.

Connector inspection: The tachometer connector is in a high-vibration, sometimes damp environment near the tub. Corroded pins are extremely common after 4-6 years, especially in humid climates or laundry rooms without ventilation. Clean pins with contact cleaner and inspect for green oxidation or blackening.

Replacement tachometer/RPS assemblies cost $25-$50 and mount with a single screw or clip.

Motor Winding Check

If the tachometer tests good but the drum moves sluggishly or not at all (suggesting the motor itself is the problem, not the sensor), test the motor windings:

Disconnect the motor connector from the MCU board. Measure resistance across each pair of motor phase terminals. On a three-phase motor (standard for these washers), you should find three pairs that each read 4-8 ohms. All three readings should be within 0.5 ohms of each other.

A reading of OL on any pair means an open winding — the motor is burned. A significantly lower reading on one pair (especially near zero) means a phase-to-phase short. Either condition requires motor replacement ($150-$350).

The MCU Board

If tachometer and motor both pass electrical tests, and the drum spins freely by hand, the MCU's tachometer input amplifier circuit may have failed. The MCU takes the weak analog signal from the tachometer and amplifies it to a digital pulse train for counting. A failed input amplifier means the MCU never "hears" the tachometer even though it is producing good output.

MCU failure diagnosis is a process of elimination. If you have verified the tachometer's output is present (using an oscilloscope on the tach signal wire while manually spinning the motor), and the MCU still posts F25, the MCU requires replacement. Without a scope, you rely on: tach tests good + motor tests good + free-spinning drum = MCU.

MCU boards run $150-$300 depending on model.

Repair Costs and Decisions

Decision guidance: Tachometer replacement is always worthwhile — the part is cheap and the machine lives on. Motor or MCU failure on a washer under 7 years old: repair. Over 10 years with additional symptoms (tub bearing noise, rust, leaks): strongly consider replacement.

Parts Ordering

For Whirlpool-built 110.xxxxx Kenmore washers:

• Rotor Position Sensor: WPW10178988 or W10183157 (varies by sub-model)
• Motor: specific to model — enter full model number at PartSelect or RepairClinic
• MCU Board: W10756692 or equivalent (must match motor type)

These are all Whirlpool part numbers. Do not search "Kenmore tachometer" — results will be unreliable.

Important Note About Kenmore Parts Ordering

Because Kenmore is a multi-manufacturer brand (not a maker itself), parts must be ordered by the actual manufacturer's part number — not by searching "Kenmore washer parts." Your model number prefix identifies the real manufacturer:

For washers: the most common Kenmore washer manufacturer is Whirlpool (prefix 110.xxxxx for washers/dryers, 665.xxxxx for dishwashers, 790.xxxxx for ovens). Parts websites like PartSelect and RepairClinic accept your full Kenmore model number and automatically cross-reference to the correct OEM part number. Always verify the part number matches before ordering — similar-looking parts from different manufacturers are not interchangeable even though both machines say "Kenmore" on the exterior.

The Sears Parts Direct website (now Partstown) also stocks these parts but typically at a higher price point than ordering the OEM part directly from an appliance parts wholesaler. Shopping by the OEM part number rather than the Kenmore part number often saves 20-40% on identical components.

Extending Your Kenmore Washer's Lifespan

Regular maintenance prevents many error codes from developing in the first place. For your Kenmore washer, the most impactful maintenance items are:

Monthly: Run a clean cycle (dedicated Clean Washer cycle or hottest cycle with no clothes and a washer cleaner tablet). This dissolves detergent residue and mineral deposits that accumulate in the wash system, drain path, and sensor areas. Residue buildup causes false sensor readings, slow drainage, and reduced cleaning effectiveness.

Every 3-6 months: Clean the inlet screens where supply hoses connect. Hard water areas should clean every 3 months; soft water areas every 6. Also clean the drain pump filter if your model has an accessible one.

Annually: Inspect supply hoses for bulging, cracking, or discoloration. Rubber hoses should be replaced every 5 years regardless of appearance — internal deterioration is invisible until the hose bursts. Upgrade to stainless steel braided hoses for burst protection.

Always: Use the correct amount of HE detergent (if applicable). Check pockets before every load. Do not overload the drum past 3/4 capacity. Leave the door ajar between loads to prevent mold and mildew in the gasket and tub.

F25 on your Kenmore? We test tachometer, motor, and MCU on-site to pinpoint the failed component before ordering parts. No guesswork, no wasted money on the wrong part. Book your diagnostic.