03/16/21
Message Overview:
Message Description:
PSEU Discrete Output DOT25A, RETRACT CMD to Retract Valve, V9 driver failed.
Possible Causes:
- Proximity Sensor Electronic Unit (PSEU) (A9)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Proximity-Sensor Electronic Unit (PSEU) | AMM 32-61-09-000-801 |
| Installation of the Proximity-Sensor Electronic Unit (PSEU) | AMM 32-61-09-400-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
| Electrical Connectors - Maintenance Practice - ALL | SPM 20-20-00-02 |
Troubleshooting Recommendations:
- Pull and reset the PSEU gear system breakers (CB1-C13, CB1-C14, CB2-C13, CB2-C14).
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Set aircraft Power OFF and Landing Gear Control Handle to RETRACT.
- Do wiring checks between LANDING GEAR SELECTOR VALVE V9P1 pin A and PSEU A9CP1 pin 4A. Repair as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace PSEU.
- Do close out.


