What Is Behind the Electronic Components Failure in Your Land Rover Discover?
In addition to the unmatched mechanical abilities of the Land Rover Discovery, there is the advanced integration of electronics, sensors, and computing technology. One of them is the Body Control Module (BCM), which controls all the non-engine and non-drivetrain components' functioning mechanism, such as power doors and windows, interior and exterior lighting, windshield washers and wipers, alarm and security, and key fob.
A malfunction in the body control module causes erratic behavior of the electronic components that are crucial for the vehicle's function. On top of the safety and security issues, the car sometimes fails to even function.
Causes Behind BCM Module Failure in Discovery
Water Ingress and Corrosion
The Land Rover Discovery is made for off-road driving in rugged terrains. This increases the vehicle's chances of encountering water, rain, snow, and road salt. However, there are fail-safes against these factors in Discovery; component malfunctions such as a clogged sunroof drain, a leaking windshield cowl, or a bad A-pillar seal assist in BCM malfunction. The module is situated at a vulnerable position in the vehicle frame and often faces failures such as short circuits or slow and progressive corrosion.
Voltage Spikes and Electrical Shorts
The microprocessors and transistors of the body control module are highly sensitive to voltage spikes and electrical surges. These spikes can fry the internal components of the BCM and sometimes permanently damage the module. The cause of the electrical surge could be incorrect jump-starting the vehicle, a failing alternator, or a short circuit elsewhere in the wiring harness.
In the Land Rover Discovery, the body control module runs on sophisticated software that manages various components and module functions in the vehicle. A voltage drops during operation, an interrupted software update, or simply a random glitch can cause corruption in the software that negatively affects the module's operation. This results in irregularities in one or multiple component operations.
Vibration and Physical Damages
This is a rare cause of BCM malfunction in Discovery. Constant vibration from both on-road and off-road use, over many years, can cause damage to the body control module. The solder joints on the circuit board begin to crack after bearing years of strain. Also, in rare cases of an accident or improper servicing, the module itself or its connectors can suffer physical damage.
Signs and Symptoms of a Failing BCM Unit
The BCM failure does not occur in an instance. It starts small and progressively becomes worse, exhibiting the following malfunction signs:
The automatic windows and doors do not respond accurately to the command; for example, windows may open or close on their own, one window switch might operate the wrong window, doors might refuse to lock or unlock with the fob, or they might lock and unlock themselves while driving.
Similarly, the wipers might not turn on, refuse to turn off, or stop in the middle of the windshield. Also, the intermittent setting may stop working entirely.
The headlights or interior lights may stay on after turning off the vehicle, flicker erratically, or not turn on at all. The warning lights on the dashboard may also turn on erratically.
The malfunction may also cause the vehicle to not recognize the key fob, ultimately locking you out of the Land Rover Discovery.
Some components may not turn off even after the vehicle is turned off. This causes the drainage of power from the battery, causing parasitic drain in the car.
Solving the Body Control Module Malfunction in the Land Rover Discovery
Repairing the damage of the body control unit starts with the proper diagnosis of the malfunction and eliminating other possibilities. Using a Land Rover-specific diagnostic scanner like SSD and Pathfinder, the vehicle is scanned for fault codes related to BCM. The fuse and relays are checked, as damage to these can also mimic BCM malfunction. On top of these, the wiring and component grounds are inspected, along with the inspection of water ingress.
Upon identifying the malfunction in the BCM, you have two options when it comes to a solution, the first one is repair and the second one is replacement.
In cases of small and isolated malfunctions in the body control module due to corrosion and specific component damage, the module is repaired. The damaged component is repaired by a specialist in isolation, and the module is calibrated after installation. When the damage is extensive and severe, the module is replaced with a new one. The new BCM unit is an OEM-made unit that is compatible with the Land Rover Discovery.
