06/14/19
Message Overview:
Fault Message:
APU GENERATOR FAULT
Fault Code:
2420104LPS
Associated CAS:
| Reporting LRU: | Auxiliary Power Unit (APU) Generator Control Unit (GCU) |
| System Description: | 24-22-00 |
| Schematic Diagram: | 24-22-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 24-22-01 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
Auxiliary Power Unit (APU) Generator Control Unit (GCU) sense a field current greater than 3 Amps coming from the APU Generator.
Possible Causes:
- Auxiliary Power Unit (APU) Generator Control Unit (GCU) (A109)
- Auxiliary Power Unit (APU) Generator (A110)
- 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 APU Generator | AMM 24-22-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the APU Generator | AMM 24-22-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| 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 APU GCU 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 APU GCU and do close out.
- If fault remains, continue with next step.
- Disconnect APU GCU connector A109P1 and APU Generator connector A110P1.
- Perform wiring checks (open circuit = failure) as follow:
From To Result A109P1-J A110P1-H - If wiring checks are good, repair the defective associated wiring as required and do close out.
- If fault remains, continue with next step.
- Perform wiring checks (open circuit = failure) as follow:
From To Result A109P1-K A110P1-B - If wiring checks are good, repair the defective associated wiring as required and do close out.
- If fault remains, continue with next step.
- Perform wiring checks (closed circuit = failure) between A109P1-J and the aircraft structure.
- If wiring checks are good, repair the defective associated wiring as required and do close out.
- If fault remains, continue with next step.
- Perform wiring checks (closed circuit = failure) between A109P1-K and the aircraft structure.
- If wiring checks are good, repair the defective associated wiring as required and do close out.
- If fault remains, continue with next step.
- Replace APU Generator.
- Do close out.