The problem is a system I/O control logic problem. Use the following table to determine the part number for the field replaceable unit (FRU):
| CCIN or FFC | Type and model | Part number | Description | Location code |
| 221 | 8204-E8A | 10N9369 | System backplane | Un-P1 |
| 221 | 9117-MMA | 42R7352 | I/O backplane | Un-P1 |
| 221 | 9117-MMA | 03N6902 | System processor backplane | Un-P2 |