09/18/19
Message Overview:
Fault Message:
SHORT CKT-APU GCU/READY TO LOAD WRG
Fault Code:
4960184APU
Associated CAS:
| Reporting LRU: | Full-Authority Digital Engine-Controller (FADEC) |
| System Description: | 49-60-00 |
| Schematic Diagram: | 49-61-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 49-61-01 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
The generator ready to load output from the Full-Authority Digital Engine-Controller (FADEC) is on while the conditioning circuit shows the output is out of range low. The Auxiliary Power Unit (APU) is ready to load but the APU Generator does not show this condition. This shows that the APU Generator ready to load circuit or the aircraft wiring harness could have a short.
Possible Causes:
- Auxiliary Power Unit (APU) Full-Authority Digital Engine-Controller (FADEC) (A108)
- Auxiliary Power Unit (APU) Generator control Unit (A109)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
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 ] |
| APU Safety Precautions | AMM 49-00-00-910-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Engine Branched Wiring-Harness | AMM 49-12-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Engine Branched Wiring-Harness | AMM 49-12-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Full-Authority Digital Engine-Controller (FADEC) | AMM 49-61-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Full-Authority Digital Engine-Controller (FADEC) | AMM 49-61-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Examine the AC wiring harness for bare wiring, kinks, worn areas and other damage.
- If there is bare wiring, kinks, worn areas or other damage, replace APU Generator and do close out.
- If NO, continue with next step.
- Perform a wiring check between AC wiring harness (P616) and FADECA (108BP1).
- If wiring checks are not good, repair defective wiring as required and do close out.
- If wiring checks are good, continue with next step.
- Perform a continuity check between each pin that follows and the ground shell. Measurements should be open circuit.
From To Result P616-H Ground A108BP1-A4 Ground - If there is continuity, repair defective wiring as required and do close out.
- If there is no continuity, continue with next step.
- Perform a wiring check between AC wiring harness (J616) and APU generator (A109P2).
- If wiring checks are not good, repair defective wiring as required and do close out.
- If wiring checks are good, continue with next step.
- Perform a continuity check between each pin that follows and the ground shell. Measurements should be open circuit.
From To Result P616-H Ground A109P2-38 Ground - If there is continuity, repair defective wiring as required and do close out.
- If there is no continuity, continue with next step.
- Perform a check of the EICAS primary display to find EICAS messages that are related to the APU generator.
- If EICAS messages that are related to the APU generator are present, troubleshoot APU generator.
- If NO, continue with next step.
- Replace FADEC (A108).
- Do close out.