The Sauer Sundstrand KDC2067 is a programmable hydraulic‑drive controller used to regulate pump and motor speed in industrial hydrostatic systems. Common failure modes for this class of controllers include power‑supply voltage drops, overheating of the main drive IC, and degradation of the high‑current MOSFET array; these often manifest as random resets or loss of communication with the host PLC. For a first‑check diagnostic, verify that the 48 V DC rail is within spec and that all fuse and circuit‑breaker ratings are intact; then inspect the board for burn marks, cracked solder joints, or swollen electrolytic capacitors. Finally, review any stored error codes via the controller’s diagnostics port to pinpoint whether the issue lies in power delivery, signal input, or internal firmware.[oss-gpt-20b]