03/04/21
Message Overview:
Message Description:
DCU channel A not receiving L-GP BUS-5 data but data received at 3-of (SPC, FCU, L-SECU, PSEU, HSTECU, FQGC).
Possible Causes:
- Data Concentrator Unit (DCU) (A14)
- Junction Box 2 (JB2)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Junction Box JB2 | AMM 24-63-05-000-803 |
| Installation of the Junction Box JB2 | AMM 24-63-05-400-803 |
| Removal of the Data Concentrator Unit (DCU) | AMM 31-41-01-000-802 |
| Installation of the Data Concentrator Unit (DCU) | AMM 31-41-01-400-802 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset EICAS DCU A Circuit Breaker CB1-D1. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Dowiring check between DCU (A14) and IAPS Card Cage (A4), through Junction Box 2 for the following wires:
From To Result Conn. A14DP1 - 5A Conn. A4P1 - 1 Conn. A14DP1 - 5B Conn. A4P1 - 2 - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair defective wire or Junction Box 2.
- Replace DCU (A14).
- Do close out.