| Symptom | Most likely error code | Check first | |---------|------------------------|--------------| | No function, remote connected | E 03, E 31 | Receiver fuse, ECU power | | Crane moves slowly | E 20, E 21 | Oil level, cooler fan | | Boom won’t lift heavy loads | E 10 | Pressure sensor, overload setting | | Stabilizer light stays red | AL 32 | Stabilizer microswitch / proximity sensor | | Display blank but remote works | – | Backlight fuse or display ribbon cable |