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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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05/27/22

Message Overview:

Message Name:

R ESSENTIAL BUS FAILED

Message Code:

B3-007555

Associated CAS:

PROX SYS FAULT
(Advisory)

Reporting LRU: PSEU LRU
System Description: 32-60-00
Schematic Diagram: 32-61-00
Wiring Diagram: 32-61-09
32-61-12

Message Description:

Proximity Sensor Electronic Unit detects low power from 28 VDC Right Essential Bus, aircraft power interface requires troubleshooting.

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
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:

  1. Pull and reset the PSEU gear system breakers (CB1-C13, CB1-C14,CB2-C13, CB2-C14), recheck the system for the fault.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  2. Check the PSEU plug, 28 VDC power should be on the PINS 7K and 8K connector A9BP1 and ≥22 VDC.Check resistance to ground on the PINS 3H and 4H connector A9BP1. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  3. Replace the PSEU.
  4. Functional Test of the Proximity Sensor Electronic Unit (PSEU).
  5. Do the close out.

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