Read and clear this fault code yourself with the EAS Unlock V4 for the P38 Range Rover.
RL Valve Stuck Closed
This fault is indicating that there is a possible problem with the Rear Left solenoid valve. But…Be very wary of this fault code. The most likely cause of this fault code is a leak in one of the air springs or general leak in the system. Also make sure and check for a weak compressor. Find and repair all leaks in the system first. Also time how long the systems takes to pressurize the primary air tank.