semiatic

Key battery low light

The coin-cell battery inside your remote or smart key is running flat. It says nothing about the car's own 12-volt battery, which has its own red charging light.

Yellow / amber

Not defined by regulation: a maker convention

What to do

Replace the key's battery soon; the manual gives the type and how to open the key. Until you do, keyless entry and push-button start may stop recognising the key. If it goes completely dead, the car can still be started: Kia says press the start/stop button with the smart key itself, and Mazda describes holding the key over the start button while pressing the brake (or the clutch). Your manual shows the spot for your car.

Makes differ: what this light means on your car, the other colours it may use for the symbol and what the car wants you to do are set by the manufacturer, so your car's owner's manual is the authority.

Symbol
Key fob beside a small battery
Also called
Key fob battery low; Smart key battery warning; Low key battery indicator
Colour
Yellow / amber
Standard
None — a maker convention, described here from 2 makers: Kia, Mazda

Where makes differ

Kia's indicator blinks amber for a few seconds when the car is switched off; Kia's immobiliser light also blinks when the key battery is weak. Mazda shows the message 'Low Key Fob Battery. Replace Battery' when the ignition is switched off, within its KEY warning.

Not defined by regulation: a maker convention

Neither US FMVSS 101 (Tables 1 and 2) nor UN Regulation No. 121 lists this light, so no rule fixes its symbol or its colour. What follows is what the makers cited below say; other makes, and other model years of the same make, may draw it differently.

Neither FMVSS 101 nor UN R121 lists a key-battery tell-tale.

Other yellow / amber maker lights

Diesel particulate filter (DPF) lightBox full of dots with a pipe at each end · maker conventionAdBlue (DEF) warning lightLiquid container with a wavy fill line and a drop · also red · maker conventionEPCEPC (electronic power control) lightThe letters EPC · maker conventionLane assist (lane keeping) lightLane markings running away from you, dashed line in the middle · also green · maker conventionForward collision warning lightCar seen from behind with radar arcs around it · also red · maker conventionBlind spot monitor lightTwo cars side by side with signal waves between them · maker conventionAdaptive cruise control (ACC) lightSpeedometer dial with a needle · also green · maker conventionAUTOHOLDAuto Hold lightThe words AUTO HOLD · also green · maker conventionPower steering warning light (EPS)Steering wheel, sometimes with an exclamation mark · also red · maker conventionWater in fuel light (diesel)Fuel pump with water drops beside it · maker conventionGearbox (transmission) warning lightCog wheel with an exclamation mark · maker convention?Key not detected lightKey with a question mark · maker conventionBulb failure (exterior light) warningLight bulb with rays and an exclamation mark · maker conventionHill descent control lightCar pointing down a slope · also green, red · maker conventionAAuto stop-start lightLetter A inside a circular arrow · also green · maker conventionService due (spanner) lightA spanner (wrench) · maker conventionLow engine oil level lightOil can above a wavy level line · maker conventionFrost / icy road warning (snowflake)A snowflake · maker conventionLow washer fluid lightWindscreen with a dashed fountain of spray · maker conventionImmobiliser (security) lightCar outline with a key inside it · also red · maker conventionReduced power (tortoise) lightA tortoise · maker conventionPedestrian warning sound off or faultyWalking figure with sound waves · maker convention4WD / AWD warning lightFour wheels joined by axles and a drive shaft · maker convention

All yellow / amber dashboard lights, regulated ones included

Sources

No regulation defines this light, so it is described from 2 carmakers' own manuals or owner pages, each fetched and checked on the date shown:

Written in our own words; the makers' pages cover their own models only.