Discovery 4 Interior Ultrasonic Alarm Sensor AH42-15K609-AC Land Rover

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♻️ GENUINE LAND ROVER DISCOVERY 4 L319 INTERIOR ULTRASONIC MOTION ALARM SENSOR – AH42-15K609-AC

Genuine used Land Rover Discovery 4 L319 interior ultrasonic / motion alarm sensor module, designed for the factory vehicle security and interior monitoring system.

This sensor monitors movement within the passenger compartment when the vehicle alarm system is armed and helps detect unauthorised entry or movement inside the vehicle.

Part Number: AH42-15K609-AC

Alternative Format: AH4215K609AC

OE / Cross Reference: LR019354

Related Engineering Reference: AH42-15K609-A

Part Type: Interior Ultrasonic Alarm Sensor / Motion Sensor

System: Vehicle Security / Interior Alarm Monitoring

Position: Interior / Roof Area

Manufacturer: Land Rover / OEM

Condition: Genuine Used

Compatibility

Confirmed applications include:

• Land Rover Discovery 4 L319 – 2009–2016

• Discovery 4 2.7 TDV6 applications where matching equipment is fitted

• Discovery 4 3.0 TDV6 / SDV6 applications where matching equipment is fitted

• Vehicles equipped with the factory interior alarm / volumetric monitoring system

The exact AH42-15K609-AC number is specifically documented as a Discovery 4 L319 interior ultrasonic alarm sensor. Used-parts references also show it on both 2.7 TDV6 and 3.0 TDV6 Discovery 4 applications.

Additional Applications

The same AH42-15K609-AC engineering number is also documented on selected:

• Range Rover Sport L320

• Range Rover L322

where the same factory interior alarm sensor system is installed.

Compatibility with these vehicles should be confirmed by matching the complete engineering number and electrical connector.

Technical Information

This module forms part of the Land Rover factory anti-theft alarm system.

The ultrasonic / motion monitoring system is designed to detect movement inside the passenger compartment after the vehicle has been locked and the alarm system has been armed.

The sensor communicates with the vehicle security system so that detected interior movement can contribute to an alarm activation.

Vehicle Security System Information

The sensor works together with components including:

• Vehicle alarm system

• Body Control Module / security electronics

• Door and tailgate monitoring

• Bonnet monitoring

• Central locking system

• Alarm siren

• Interior volumetric / ultrasonic monitoring system

• Associated wiring and electrical connectors

This allows the vehicle to monitor not only the doors and other entry points but also movement inside the cabin when interior monitoring is active.

Common Symptoms / Reasons for Replacement

• Alarm triggering unexpectedly

• False alarm activations

• Interior monitoring not operating

• Alarm system fault

• Diagnostic fault relating to interior monitoring

• Sensor damaged during headlining removal

• Electrical connector damaged

• Water or moisture damage

• Internal sensor failure

• Original sensor missing

• Replacement following interior or roof repairs

Important Diagnostic Information

False alarms do not automatically mean that the ultrasonic sensor is faulty.

Before replacement, check:

• Alarm system fault codes

• Sensor electrical connector

• Wiring and power supply

• Door and tailgate switches

• Bonnet switch

• Alarm siren system

• Interior monitoring configuration

• Evidence of moisture or water ingress

Movement inside the vehicle, open windows or other security-system faults may also affect alarm operation.

Correct diagnostic testing is recommended before replacing electronic security components.

Installation

The module is installed within the vehicle interior / roof area as part of the factory alarm monitoring system.

When replacing:

• Disconnect the electrical connector carefully

• Avoid pulling on the wiring

• Check terminals for corrosion or damage

• Ensure the sensor is securely mounted

• Refit surrounding interior trim correctly

Care should be taken when removing roof/headlining trim because plastic retaining clips can become brittle with age.

Programming / Coding

For a like-for-like replacement using the identical AH42-15K609-AC specification, separate programming may not always be necessary.

However, because this component operates as part of the vehicle security system, the alarm system should be checked with suitable diagnostics after installation if faults remain.

Any stored fault codes may need to be cleared after the underlying problem has been repaired.

Important Compatibility Note

⚠️ Please match the complete part number before purchasing.

Check:

• AH42-15K609-AC

• AH4215K609AC

• LR019354 where applicable

• Electrical connector

• Sensor housing

• Mounting arrangement

• Factory alarm specification

• Listing photographs

Although the same sensor is documented across several Land Rover applications, do not purchase solely by vehicle model and year.

Matching the original part number is the safest way to confirm compatibility.

Condition

Genuine used Land Rover part.

May show normal signs of previous use, removal and storage, including light cosmetic marks.

Please inspect all supplied photographs carefully for the exact condition, connector and mounting points of the item supplied.

♻️ Genuine Land Rover Discovery 4 L319 interior ultrasonic / motion alarm sensor AH42-15K609-AC – ideal replacement for a damaged or faulty factory interior alarm monitoring sensor.