Symptoms
Slow to rise, 'suspension fault' message, compressor running constantly or overheating, truck stuck at a low height.
The fix, step by step
- Find the leak first, or a new compressor will burn out too: raise the truck, pull the EAS fuse overnight and measure each corner, and soap-test struts, valve blocks and Voss fittings.
- Fit the new compressor with a new relay, and don't overtighten the Voss fittings.
- LR4s left the factory with Hitachi or, later, AMK units, and the EAS software must match the pump fitted, so recalibrate with a dealer tool or a GAP IIDTool.
- The compressor sits low beside the sill, which is why some rock sliders are designed to shield it.
Tools & part numbers
- Jack and stands, sockets, soapy water, GAP IIDTool or dealer diagnostics
- compressor (Hitachi LR023964 or AMK LR072537), relay
Where to buy the parts
LR4 air suspension compressor searchAtlantic British ↗
Hunting a used or discontinued part? Search eBay Motors for Land Rover LR4 / Discovery 4 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.