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Key Not Detected Or Keyless Start Not Working

A "key not detected" message usually means the key battery is weak, the key is too far from the antenna, there is radio interference, or the key or receiver has a fault.

Normal risk

Not dangerous. Most cars have a backup way to start with a flat key battery.

Short answer · Why does my car say key not detected?

Keyless systems use low-power radio signals between the key and antennas in the car. A weak key battery is the most common cause. Phones, chargers or metal objects next to the key can interfere. Most cars let you hold the key against a marked spot or place it in a slot to start even with a flat key battery; the owner's manual shows where.

On this page

Safe checks you can do

  1. Use the backup positionHold the key against the marked spot on the steering column or start button.
  2. Replace the key batteryThis often fixes it.
  3. Move interference awayKeep the key away from phones, chargers and metal.

Questions that narrow it down

  1. Does the spare key work?If yes, the main key or its battery is faulty.
  2. Is the car battery also weak?The car may not power its antennas properly.
  3. Does it happen in one place only?Local radio interference is likely.

Possible causes

Listed without ranking. Use the questions above to see which ones fit your car.

  1. Weak key batteryMost common cause.
  2. Radio interferencePhones, chargers, nearby transmitters.
  3. Faulty keyDropped or wet keys fail.
  4. Antenna or receiver faultIn the car.
  5. Weak car batteryLow voltage affects the system.

Questions about Key Not Detected Or Keyless Start Not Working

How often should a key battery be changed?

Every few years, or when range drops or warnings appear.

Can I program a new key myself?

Usually not; most need dealer or locksmith equipment.