Borgwarner
FK72-4C170-AA Haldex control unit Land Rover Used
FK72-4C170-AA Haldex control unit Land Rover Used
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Used OEM Haldex Control Unit FK72-4C170-AA – Land Rover AWD
Original BorgWarner rear differential control module for Land Rover and Range Rover AWD vehicles with Haldex Gen 5 Efficient Driveline system.
OEM Part Numbers & Cross-References
FK72-4C170-AA • FK724C170AA • FK72 4C170 AA
LR073537
116260 • EGP6A • ALMG3
Technical Specifications
Product Description
This is a genuine used original BorgWarner Haldex control unit with part number FK72-4C170-AA, Land Rover OEM reference LR073537, designed for Land Rover and Range Rover Active On-Demand AWD systems using the Haldex Gen 5 Efficient Driveline setup. Known as the RDCM, this unit is the electronic brain of the rear coupling and manages rear-wheel-drive engagement when traction is needed.
What This Control Unit Does
- Monitors wheel-speed differences between front and rear axles via ABS sensors
- Controls the hydraulic pump to build rear clutch engagement pressure
- Activates rear-wheel-drive engagement on demand
- Communicates with ABS, ESP, TCM, BCM and engine management via CAN-bus
- Manages oil temperature monitoring and thermal overload protection
- Supports Terrain Response and Hill Descent Control integration
Vehicle Compatibility
The FK72-4C170-AA fits Land Rover and Range Rover models equipped with the Haldex Gen 5 Efficient Driveline AWD system. Always verify the part number on your existing unit and confirm your vehicle has Haldex Efficient Driveline, not the GKN Dynamic Driveline variant.
Land Rover / Range Rover
- Land Rover Discovery Sport (L550) – 01/2015 to 12/2019
- Range Rover Evoque I (L538) – 09/2015 to 12/2018
- Range Rover Evoque II (L551) – 01/2016 to 12/2019
- Vehicles fitted with Haldex Gen 5 Efficient Driveline AWD only
Common Diagnostic Fault Codes & Symptoms
A faulty Haldex Gen 5 RDCM in Land Rover / Range Rover models can stop AWD operation or cause intermittent drivetrain faults. Common diagnostic issues and symptoms include:
-
U0001-00– High Speed CAN Communication Bus fault -
U0100-00– Lost Communication With ECM / PCM -
U0121-00– Lost Communication With ABS Control Module -
U0138-00– Lost Communication With All Terrain Control Module -
U0140-00– Lost Communication With Body Control Module -
U0300-00– Internal Control Module Software Incompatibility -
U2101-00– Control Module Configuration Incompatible -
P1889-74,P1889-14,P1889-49– Oil pressure pump performance faults -
P0748-14– Pressure Control Solenoid A fault -
P0607-49/P0602-54– Internal control module or programming faults - Dashboard warnings such as HDC Fault System Not Available, Transmission Fault and Traction Reduced
- Loss of 4WD / AWD engagement, occasional non-start conditions, or grabbing / skipping in tight turns
Installation & Calibration
Installation Steps
- Locate the Haldex RDCM on the rear differential / coupling housing
- Disconnect the electrical connector and remove the mounting bolts
- Carefully detach the old control unit from the coupling housing
- Fit the replacement unit and secure all mounting points to the correct torque
- Reconnect the electrical connector and verify a secure fit
- Connect a Land Rover-compatible diagnostic tool and program the unit to the vehicle VIN
- Clear all stored fault codes and perform a test drive to verify AWD operation
Recommended Maintenance at Time of Replacement
- Replace Haldex Gen 5 oil and clean the pump gauze strainer
- Inspect the electrical connector and wiring harness for corrosion or damaged pins
- Check the rear differential breather pipe for blockage
- Verify 12V power supply fuses for the Haldex system
- Clear all stored fault codes after installation and perform a test drive
Why Haldex Control Units Fail
1. Water Ingress & Corrosion
The RDCM is mounted in an exposed undercarriage position where moisture can enter over time, corroding the PCB and causing communication failures or complete shutdown.
2. Oil Pump Failure & Pressure Loss
A blocked pump gauze or failing pump motor causes incorrect pressure values and can disable AWD operation while logging pump performance faults.
3. Software / Programming Issues
Incorrect VIN programming or software incompatibility after battery or ECU work can prevent the RDCM from communicating with other modules, resulting in AWD loss without a mechanical fault.
4. Heat & Thermal Stress
Repeated AWD engagement under load can generate heat that degrades solder joints and internal electronics, leading to intermittent faults that worsen over time.
Quality Assurance & Warranty
12-Month Warranty: This used Haldex control unit has been fully tested and is backed by a 12-month warranty covering functional defects under normal operating conditions.
Warranty Coverage Includes:
- Electronic control unit malfunctions
- CAN-bus communication failures with AWD / ABS / BCM modules
- Pump control circuit defects
- Internal calibration memory errors
Warranty Exclusions:
- Incorrect installation
- Failure to program the unit to the vehicle VIN
- Incompatible vehicle fitment, including GKN Dynamic Driveline vehicles
- External electrical faults or physical damage during handling
Questions or Need Help?
Our technical team is ready to assist with compatibility checks, coding guidance and installation support.
Contact UsImportant Purchase Information
- Please verify the part number on your existing unit before ordering
- Confirm your vehicle has the Haldex Efficient Driveline system, not the GKN Dynamic Driveline variant
- This unit must be programmed to the vehicle VIN after installation
- Replace Haldex Gen 5 fluid during installation for best results
- Worldwide shipping is available
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