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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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03/15/21

Message Overview:

Message Name:

MLGWOW APU DRV FAIL

Message Code:

B3-007607

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
49-61-01
49-61-01

Message Description:

PSEU Discrete Output DOT06A, MLGWOW to Auxiliary Power Unit (A39) driver failed.

Possible Causes:

  • Proximity-Sensor Electronic Unit (PSEU) (A9)
  • Auxiliary Power Unit Electronic Control Unit (APU ECU) (A39)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

MLGWOW (06A) GND/OPEN Discrete 49 (WOW) ARINC APU is shut down automatically on failure on ground. In air, pilot has to shut down.
PSEU discrete block diagram

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
Removal of the Auxiliary Power Unit (APU) Electronic Control Unit (ECU) AMM 49-61-01-000-801
Installation of the Auxiliary Power Unit (APU) Electronic Control Unit (ECU) AMM 49-61-01-400-801
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).

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

  2. Do wiring check between APU ECU A39AP1 pin 13C and PSEU A9CP1 pin 6A. Repair as required.

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

  3. Replace PSEU.
  4. Do close out.

60_lh_cbpnl60_rh_cbpnlpseu_location

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