06/25/19
Message Overview:
Fault Message:
GCU1 PIN PROGRAMMING FAULT
Fault Code:
2421128LPS
Associated CAS:
| Reporting LRU: | Generator Control Unit (GCU) 1 |
| System Description: | 24-21-00 |
| Schematic Diagram: | 24-21-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 24-21-01 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
Generator Control Unit (GCU) 1, during initial power-up (cold start), has detected a fault in the pin programming wiring or in the pin programming sensing circuit, consequently the Generator will not come on-line.
Possible Causes:
- Generator Control Unit (GCU) 1 (A56)
- Associated Wiring
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 ] |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Swap GCU #1 with GCU #2 (physically or using the GCU patch cable).
NOTE: Use PMAT to monitor the fault on GCU.- If system checks are good, replace GCU #1 and do close out.
- If fault remains, continue with next step.
- Disconnect connector A56P2 and perform wiring checks on GCU #1 as follow:
From To Expected Result Result A56P2-27 A56P2-43 Open A56P2-17 A56P2-35 Open A56P2-26 A56P2-44 Open A56P2-18 A56P2-34 Short - If wiring checks are good, do close out.
- If wiring checks are not good, repair defective wiring and do close out.
- Do close out.