Why Your Land Rover Discovery Key Randomly Stops Working in the Morning

A Land Rover Discovery key that works fine most of the time but shows a key not detected warning first thing in the morning is a specific pattern with a small number of likely causes. We see this on Discovery 5 and Discovery Sport models fairly regularly and the explanation is almost always one of the following.

1. The 12V Battery Has Partially Discharged Overnight

If the Discovery is parked overnight in cold weather or if the 12V battery is aging, it can drop to a voltage that is below the KVM’s reliable operating threshold during the cold hours of the morning. As the battery warms up slightly or the vehicle draws power from elsewhere, the voltage recovers and the key starts working again. This presents as an intermittent morning-only fault. A 12V battery load test will usually confirm if this is the cause. The battery may need replacing rather than the key system.

2. Temperature Affects the Fob Battery

CR2032 batteries are mildly temperature-sensitive. In cold weather, battery output voltage drops temporarily. A fob battery that is already borderline will lose enough output in cold conditions to drop below the reliable threshold for passive entry. The key appears not to work until the fob warms up in your hand. The fix is a fresh fob battery.

3. Moisture or Condensation in the Fob

A key that has been exposed to moisture — even briefly — can develop intermittent faults as the residual moisture causes micro-corrosion on the PCB contacts. Cold mornings with condensation can temporarily trigger these contacts. If the key looks fine externally but has a history of water exposure, internal damage may be the cause.

4. Antenna Location Matters

If you leave the key in the same location every night — on a specific surface, near another device, or in a bag — and the fault always occurs in the morning, consider whether the storage location is affecting the key’s signal. Keys stored near wireless chargers, near other key fobs, or on metal surfaces can have their signal temporarily disrupted.

Service	AJ Auto Price	Main Dealer Estimate
Land Rover spare key	From £180	£400 to £900+
Land Rover all keys lost	From £250	£700 to £1,500+

For Discovery and Discovery Sport key services see our Discovery 5 key replacement page, Discovery Sport key replacement page, and the Land Rover key replacement page.

Frequently Asked Questions

What is the most common reason a Discovery key suddenly stops working?

The most common cause is the 12V battery dropping below the voltage threshold the security system requires. This happens gradually and often first shows as intermittent key detection in the morning when the battery is coldest.

Could the key itself be the fault rather than the car?

Yes. The key fob battery is a common culprit, particularly if the problem is intermittent. A fob that detects fine in warm conditions but fails in cold weather usually has a weak fob battery struggling with temperature-related voltage drop.

Can parking near certain objects affect Discovery key detection?

Yes. Relay attack protection features on some models reduce key sensitivity in certain environments. Additionally, large metal structures, underground car parks and certain building materials can attenuate the key signal enough to prevent detection.

If the key stops working in the morning, does it get worse over time?

An intermittent morning fault that resolves after a short period typically indicates a marginal battery condition. Left unaddressed, it will progress to more frequent failures before eventually failing completely.

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