06/26/19
Message Overview:
Fault Message:
GCU3 [RS422 TRANSMIT]
Fault Code:
2423177LPS
Associated CAS:
| Reporting LRU: | Generator Control Unit (GCU) 3 |
| System Description: | 24-21-00 |
| Schematic Diagram: | 24-21-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 24-21-03 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
The Generator Control Unit (GCU) 3 has detected a RS422 transmission failure during loopback test by continuous monitoring. Even though it can no longer communicate with the AC Power Center (ACPC) through the RS422 bus, the GCU remains operational.
Possible Causes:
- Generator Control Unit (GCU) 3 (A58)
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
A GCU patch cable (GSE REF # 24X-24-02) can be used to swap GCUs 1, 4 and 5 into position 2 or 3 (for troubleshooting only).
The GCU NVMs can only be downloaded at position #2 or #3.
Quick Links:
| Removal of the Generator Control Units (GCU) | AMM 24-24-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Generator Control Units (GCU) | AMM 24-24-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Replace GCU #3.
NOTE: Use PMAT to monitor the fault on GCU. - Do close out.