Defender central locking/alarm

Central locking appeared to not be working on key fob,opened drivers door manually but as soon as ignition switched in alarm sounding & no starter,could this be the ultrasonic alarm gadget above the drivers door

No, it suggests that u didn’t unset the security system with a functioning fob. Therefore as you have found out the alarm is still set and engine immobilised.

Oh dear have two fobs & put new batteries in each neither seem to unlock the central locking or cancel the alarm ,does the ultrasonic detector not activate these systems

Cheerful said:

Oh dear have two fobs & put new batteries in each neither seem to unlock the central locking or cancel the alarm ,does the ultrasonic detector not activate these systems

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Have you resynchronised the fobs after the battery change, see paragraph 7 (its from the 300 user manual but expect yours is the same)

Cheerful said:

Oh dear have two fobs & put new batteries in each neither seem to unlock the central locking or cancel the alarm ,does the ultrasonic detector not activate these systems

Click to expand...

It detects movement within the vehicle, and then activates the alarm only when the alarm is set.