Milwaukee Cordless Vacuums Error Codes

BATTERY CHARGER – RED/GREEN FLASHING

When charging the vacuum’s M18 battery, the Milwaukee charger LED flashes red and green alternately and the battery will not charge.

Battery Pack Fault (Charger Reject)

BATTERY CHARGER – SOLID RED, NO GREEN

Battery placed on charger for the vacuum remains on solid red for an unusually long time and never turns green.

Battery Not Reaching Full Charge

FAST RED FLASHING (ON TOOL)

Vacuum will not start; LED on the tool flashes red rapidly as soon as trigger is pulled.

Low Voltage or Battery Under-Voltage Lockout

LED BAR GRAPH BLINKING (ON TOOL, MULTI-SPEED MODELS)

On models with multiple speed LEDs, the bar graph blinks and the vacuum reduces power automatically.

Electronic Current Limiting / Soft Overload

NO LED / NO RESPONSE

Battery is installed, but the vacuum shows no lights and does not respond to the trigger.

Main Power Circuit Open

RED/GREEN FLASH (ALTERNATING)

Vacuum will not run; LED on the tool alternates red and green when trigger is pulled.

Battery Pack Communication Fault

SLOW RED FLASHING (ON TOOL)

Vacuum runs briefly then stops; LED flashes red slowly and repeatedly.

Thermal Overload Protection

SOLID RED LED (ON TOOL)

Vacuum stops running and a solid red LED on the tool remains lit.

Overload or Overcurrent Protection Trip

Symptom

Dust escapes from around the canister or filter area during use.

Filtration System Leak

Symptom

Hose kinks easily and restricts airflow during use.

Collapsed or Fatigued Hose

Symptom

LED work light on the vacuum does not turn on, but the motor runs normally.

LED Indicator/Work Light Failure

Symptom

Liquid leaks from the bottom of the canister during or after wet vacuuming.

Canister Seal or Drain Plug Leak

Symptom

Trigger feels loose or does not spring back, and the vacuum will not start.

Mechanical Trigger Failure

Symptom

Vacuum does not respond after being stored for a long period.

Storage-Related Battery or Contact Issues

Symptom

Vacuum emits a high-pitched whistling noise and suction seems reduced.

Air Leak at Seal or Hose Connection

Symptom

Vacuum emits an unusual chemical or plastic smell during first uses.

Normal Break-In or Mild Overheating

Symptom

Vacuum handle or housing cracks near the battery or canister mount.

Structural Housing Damage

Symptom

Vacuum intermittently loses suction when the hose is twisted or rotated.

Intermittent Hose Blockage or Internal Collapse

Symptom

Vacuum leaves fine dust on surfaces and exhaust air seems dusty.

Ineffective Fine Dust Filtration

Symptom

Vacuum leaves streaks or debris lines when using the floor nozzle.

Nozzle Blockage or Worn Brush/Lip

Symptom

Vacuum makes loud grinding or screeching noises when running.

Motor Bearing or Fan Damage

Symptom

Vacuum motor runs but there is no suction at the nozzle.

Major Air Leak or Disconnected Suction Path

Symptom

Vacuum motor speed surges up and down without changing the trigger or speed setting.

Unstable Motor Control or Power Supply

Symptom

Vacuum produces a burning smell or visible smoke from the motor area.

Motor Overheating or Electrical Short

Symptom

Vacuum produces static shocks to the user during operation, especially in dry environments.

Static Electricity Buildup

Symptom

Vacuum runs but suction is very weak even with a fully charged battery.

Restricted Airflow or Air Leak

Symptom

Vacuum runs but the hose or wand gets extremely hot near the handle.

Severe Airflow Restriction or Electrical Heating Near Handle

Symptom

Vacuum runs only at one speed even though it has multiple speed settings.

Speed Selector or Control PCB Fault

Symptom

Vacuum runtime is significantly shorter than specified, even with a fully charged battery.

Excessive Current Draw or Battery Capacity Loss

Symptom

Vacuum shuts off after a few seconds of use but restarts after waiting a short time.

Intermittent Thermal or Overcurrent Trip

Symptom

Vacuum shuts off immediately when tilted or carried by the handle.

Internal Connection or Safety Interlock Issue

Symptom

Vacuum vibrates excessively during operation, especially at higher power.

Imbalanced Fan or Loose Internal Components

Symptom

Vacuum will not pick up liquids even though it is a wet/dry model.

Wet Pickup Configuration or Float Valve Issue

Symptom

Vacuum will not turn on unless the battery is held or wiggled in a certain position.

Intermittent Battery Connection

Symptom

Vacuum’s battery drains while the tool is stored attached, even when not in use.

Parasitic Standby Drain