Pump Boss 990394‑10 is a wireless remote control and monitoring unit used on concrete pumps, featuring an IP65/66 rated receiver, CANbus (J1939/CANopen) interface, 4‑20 mA follower output, and local start/stop capability. Common failure points for this class include power supply degradation (especially under high ambient temperatures), CANbus communication loss due to cable wear or connector corrosion, and firmware corruption leading to unresponsive remote commands. First‑check diagnostics: verify the 12 V DC input voltage and polarity; inspect the CANbus termination resistors and cable continuity; review any stored error codes on the LCD display or via a diagnostic port for communication or sensor faults.[oss-gpt-20b]