03/11/21
Message Overview:
Message Description:
PSEU detects an internal SHORT circuit in the proximity sensor PX01 Right Main Landing Gear WOW1 or the wiring to the proximity sensor is shorted to the aircraft.
Possible Causes:
- Proximity-Sensor Electronic Unit (PSEU) (A9)
- Main Landing-Gear Weight-On-Wheels 1 Proximity-Sensor (PX01)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Operational Test of the Proximity Sensors (PX01) | AMM 32-61-00-710-801 |
| Functional Test of the Proximity Sensors (PX01) | AMM 32-61-00-720-801 |
| Adjustment of the Proximity Sensors | AMM 32-61-00-820-801 |
| Removal of Main Landing Gear (MLG) Proximity Sensors (PX01) | AMM 32-61-01-000-801 |
| Installation of Main Landing Gear (MLG) Proximity Sensors (PX01) | AMM 32-61-01-400-801 |
| 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 |
| Functional Test of the Proximity Sensor Electronic Unit (PSEU) | AMM 32-61-09-720-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
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.
- Separate P514 and J514.
- Perform continuity check of RIGHT MAIN GEAR WOW 1 (INBOARD) Proximity Sensor PX01 (shorted to ground = failure). Repair as required.
From: To: Expected Results: PSEU P514 Pin 4 GND ∞Ω (Open) PSEU P514 Pin 5 GND ∞Ω (Open) - If continuity checks fail, replace RIGHT MAIN GEAR WOW 1 (INBOARD) Proximity Sensor PX01.
- Reconnect P514 and J514 and continue with next step.
- Does B3-007415 MDC Fault Code clear?
- If YES, do close out.
- If NO, continue with next step.
- Do continuity wiring check between PSEU A9AP1 and RIGHT MAIN GEAR WOW 1 (INBOARD) Proximity Sensor PX01. Repair as required.
From: To: Expected Results: PSEU A9AP1 Pin 1A J514 Pin 4 ≈0Ω PSEU A9AP1 Pin 2A J514 Pin 5 ≈0Ω - If wiring checks are good, do close out.
- If fault remains, continue with next step.
- Do continuity check of RIGHT MAIN GEAR WOW 1 (INBOARD) Proximity Sensor PX01. Repair as required.
CAUTION: Sensor resistance should be made with a meter using a < 10 mA supply of current. Never apply voltage through a sensor!
Current will magnetize the sensor rendering it unreliable.
From: To: Expected Results: PX01 P514 pin 4 P514 pin 5 11 - 13 Ω - If PX01 checks are good, do close out.
- If fault remains, continue with next step.
- Replace PX01.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace PSEU.
- Do close out.
