03/31/21
Message Overview:
Message Description:
L-CDU-6 bus is reported missing by the TSS. L-CDU-6 is not reported failed by the L-HF and L-NAV.
Possible Causes:
- Traffic Alert and Collision-Avoidance System (TCAS) Transceiver (TSS-4100) (A238)
- Junction Box (JB3)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Junction Box JB3 | AMM 24-63-09-000-802 |
| Installation of the Junction Box JB3 | AMM 24-63-09-400-802 |
| Removal of the Traffic/Collision Avoidance System (TCAS) and Traffic Surveillance System (TSS) Transponder Unit | AMM 34-43-03-000-801 |
| Installation of the Traffic/Collision Avoidance System (TCAS) and Traffic Surveillance System (TSS) Transponder Unit | AMM 34-43-03-400-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Repair Wiring | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset TCAS/XPDR 1 Circuit Breaker CB1-A5. Is the fault message still present?
- If YES, continue with next step.
- If NO, do close out.
- Do wiring check between Traffic/Collision Avoidance System (TCAS) and Traffic Surveillance System (TSS) Transponder Unit (A238) and the Junction Box No. 3 (JB3) for the following wires:
From To Results A238BP1 - D1 JB3DP1 - 4K A238BP1 - C1 JB3DP1 - 5A - If wiring check is not satisfactory, repair the defective wire.
- If wiring check is satisfactory, continue with next step.
- Replace Traffic/Collision Avoidance System (TCAS) and Traffic Surveillance System (TSS) Transponder Unit (A238). Is the fault message still present?
- If YES, continue with next step.
- If NO, do close out.
- Replace the Junction Box No. 3 (JB3).
- Do close out.