Remedy: 1 Check cable for continuity between engine controller board connector LVCN and HVPS ACN5 connector. Check cable for continuity between I/O board DCN21 and HVPS ACN5 connector. Also check for shorted pins. Is cable okay? Go to step 2. Replace cable. 2 Replace LVPS. Does problem persist? Go to step 3. Problem solved. 3 Replace engine controller board. Does problem persist? Replace I/O board. Problem solved.