The 2020+ Defender isn’t just an off-roader—it’s a rolling supercomputer with more processing power than the Space Shuttle.
The original Land Rover Defender was a masterpiece of mechanical simplicity. With roughly a dozen electronic control units managing basic functions, a competent mechanic with a socket set could tackle most repairs. The 2020+ Defender L663 is a different beast entirely—and understanding its technology is essential for any owner who wants to maintain their vehicle.
How Many ECUs Does the 2020+ Defender L663 Have?
The new Defender features more than 85 networked electronic control units—a dramatic increase from the original’s dozen or so. These ECUs manage everything from engine performance and transmission behaviour to climate control, terrain response, and advanced driver assistance systems.
The L663 was also among the first Land Rovers to implement automotive ethernet—a high-bandwidth network capable of 100 Mbps data transfer. This was necessary to support the vehicle’s multiple camera systems streaming high-definition video for features like ClearSight Ground View.
What Systems Does Terrain Response 2 Control?
Terrain Response 2 doesn’t just adjust one parameter—it orchestrates eight vehicle systems simultaneously:
- Throttle mapping– Pedal sensitivity adjusted for surface grip
• Transmission– Shift points and torque converter behaviour
• Differential locks – Centre and rear engagement strategy
• Stability control – Intervention thresholds adjusted
• Air suspension – Ride height from -50mm to +75mm
• Traction control – Wheel slip allowance calibration
• ABS calibration – Braking behaviour for conditions
• Steering weight – Power steering assistance levels
The system’s Auto mode uses data from wheel speed sensors, steering angle sensors, yaw rate sensors, and accelerometers to continuously assess conditions and adjust settings faster than any human could.
What is ClearSight Ground View?
ClearSight Ground View creates a virtual “transparent bonnet” by stitching feeds from multiple cameras. A forward-facing camera beneath the grille captures ground directly ahead, while door mirror cameras provide peripheral coverage. The system displays what appears to be a view through the bonnet itself—invaluable for navigating rocky terrain or tight trails where wheel placement is critical.
The Defender’s wade sensing system is equally impressive. Ultrasonic sensors in the door mirrors measure water depth in real-time, displaying information on the touchscreen as you enter a crossing—supporting the vehicle’s 900mm maximum wading depth.
Why This Matters for Defender Owners
This technological sophistication fundamentally changes what it means to maintain and repair a Defender. When a warning light illuminates, the underlying cause might involve communication between multiple domain controllers. A generic OBD-II code reader only scratches the surface of what’s happening.
Consider a common scenario: an air suspension fault. Without proper documentation, the assumption is often compressor failure—an expensive repair. With factory-specification workshop documentation, owners can follow a logical diagnostic sequence: checking for leaks, verifying sensor readings, testing compressor operation. Often the culprit is a slow leak or miscalibrated height sensor—repairs costing tens rather than hundreds of pounds.
Even seemingly simple tasks have electronic dimensions. Rear brake pad replacement requires putting the electric parking brake into service mode—a procedure that demands specific steps. Attempting the job without this knowledge risks damaging actuators or leaving systems in fault states.
The Bottom Line
The 2020+ Defender proves that rugged capability and cutting-edge technology aren’t mutually exclusive. This vehicle can wade through water nearly a metre deep while its 85+ ECUs monitor and optimise every system in real-time.
For owners who want to understand their vehicle beyond the dashboard warnings, a comprehensive Defender L663 workshop manual provides the factory procedures and wiring diagrams that transform complex diagnostics from guesswork into systematic problem-solving. The tools have evolved, but the satisfaction of understanding and maintaining a capable vehicle remains unchanged
