How the ACE System Works
The Active Cornering Enhancement system uses hydraulic actuators mounted at each end of the front and rear anti-roll bars to actively control body roll during cornering. A high-pressure hydraulic pump driven by the engine generates system pressure. An ACE valve block controls the distribution of hydraulic pressure to the actuators. Lateral acceleration sensors (G-sensors) and steering angle data feed the ACE ECU, which calculates how much counterforce each actuator needs to apply to keep the body flat through a corner. The result is an SUV that handles with significantly less lean than its weight and center of gravity would suggest. The system is fitted to the L322 Range Rover and L320 Range Rover Sport with the 4.4L engine; later models transitioned to electronically controlled air suspension without the hydraulic ACE architecture.
Common ACE Failure Points
High-Pressure Pump
ACE Valve Block
Hydraulic Lines and Actuators
G-Sensors and Wiring
Symptoms by Stage
The Diagnostic Approach
ACE system faults are one of the areas where JLR SDD diagnostic tooling provides a clear advantage over generic OBD scanners. The ACE ECU logs pressure data, sensor inputs, and actuator response times that tell a trained technician exactly which component is the weak link. A generic code reader sees "ACE system fault" — SDD shows you which actuator circuit, what pressure was logged at fault, and whether the pump was operating within spec. This matters because ACE repairs aren't cheap, and ordering parts based on generic fault codes is a reliable path to unnecessary repairs. Our trained technicians do the diagnostic read before recommending anything.