DOLPHIN says key not detected or the NFC card will not work

Remote key checks

1. Try the spare key away from the first key and other radio devices.
2. Stand beside the driver door and use the key button once rather than repeatedly pressing it.
3. If the spare works, replace the weak key battery with the correct type and orientation.
4. If the car opens but says key not detected, place the key at the DOLPHIN backup recognition position described in the manual and try the normal start sequence.

NFC card checks

1. Remove the card from a wallet containing other contactless cards or metal shielding.
2. Hold the correct face flat against the marked exterior-mirror reader for a moment.
3. Confirm the vehicle is locked or unlocked before repeating the action.
4. If another authorised key works, check whether this NFC card is still authorised for the vehicle.

Read the pattern

• One remote fails: suspect its battery, damage or authorisation.
• Only the NFC card fails: check placement, interference and authorisation.
• Every method fails and the car appears dark: treat this as a possible 12V-system symptom rather than replacing every key battery.

Do not dismantle the mirror reader or attempt to bypass the immobiliser. Preserve the exact message and which access methods worked. If no authorised method works, use BYD roadside support or an authorised repairer.