06/21/19
Message Overview:
Fault Message:
APU/APUGCU [OIL TEMP BULB/SENSE]
Fault Code:
2420249LPS
Associated CAS:
| Reporting LRU: | Auxiliary Power Unit Generator Control Unit (APU 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 Generator Control Unit (APU GCU) detects an oil temperature bulb fault or the APU GCU Sensing Circuit is detected faulty by the continuous monitoring, consequently resulting in the APU Generator being tripped off-line or not come on-line.
Possible Causes:
- Auxiliary Power Unit Generator Control Unit (APU 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 GCU 1, GCU 2, GCU 3, GCU 4 and the APU GCU into a different position (for troubleshooting only). You can monitor the GCU faults in CAIMS via the active faults page.
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:
- Disconnect APU GCU connector A109P2 and APU Generator connector A110P1. Do a continuity check as follows:
From To Result A109P2-24 Ground A109P2-60 Ground - If there is continuity, repair defective wiring as required and do close out.
- If there is no continuity, continue with next step.
- Do a continuity check as follows:
From To Result A109P2-24 A110P1-A A109P2-60 A110P1-M - If there is no continuity, repair defective wiring as required and do close out.
- If there is continuity, continue with next step.
- Swap the APU GCU with GCU 2. Is the fault still present?
- If NO, replace APU GCU and do close out.
- If YES, continue with next step.
- Replace the APU Generator.
- Do close out.