07/28/25
Message Overview:
Message Description:
Right engine thrust reverser deploy command fault 4.
[MCID 1463]
TR Deploy Command 4.
An open or short to +28 VDC on one of the TR deploy command signals to the ECU A or the ECU B was sensed.
Possible Causes:
- Aircraft Relays
- Aircraft Circuit Breakers
- Throttle Quadrant Assembly (TQA) (A51)
- Proximity Sensor Electronic Unit (PSEU) (A9)
- Brake Control Unit (BCU) (A67)
- Thrust Reverser (TR) Directional Control Unit
- Thrust Reverser (TR) Electro-Hydraulic Primary Lock (EHPL)
- Wiring Harness (W1), (W3), (W6), (W8), (W10), (W11)
- Full Authority Digital Engine Control (FADEC) Electronic Control Unit A (ECU) (A40)
- Full Authority Digital Engine Control (FADEC) Electronic Control Unit B (ECU) (A42)
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None
Flight Operation Notifications Manual (FONM): None
Quick Links:
| Standard Aircraft Configuration for Maintenance | AMM 12-00-00-867-803 |
| Electrical/Electronic Safety Precautions | AMM 24-00-00-910-801 |
| Electrostatic-Discharge Safety Precautions | AMM 24-00-00-910-802 |
| Connect Electrical Power to the Aircraft | AMM 24-00-00-861-801 |
| Removal of the FADEC Electrical Harness from the Right Engine | AMM 71-50-05-000-803 |
| Installation of the FADEC Electrical Harness on the Right Engine | AMM 71-50-05-400-803 |
| Removal of the Engine Electronic Control Unit (ECU) | AMM 76-10-05-000-801 |
| Installation of the Engine Electronic Control Unit (ECU) | AMM 76-10-05-400-801 |
| Removal of the Thrust-Reverser Harness (Multiplexer to Lower Deploy Switch and Electro-Hydraulic Primary Lock) | AMM 78-33-06-000-801 |
| Installation of the Thrust-Reverser Harness (Multiplexer to Lower Deploy Switch and Electro-Hydraulic Primary Lock) | AMM 78-33-06-400-801 |
| Removal of the Thrust-Reverser Harness (Multiplexer to Direction Control Unit and Upper Deploy Switches) | AMM 78-33-06-000-802 |
| Installation of the Thrust-Reverser Harness (Multiplexer to Direction Control Unit and Upper Deploy Switches) | AMM 78-33-06-400-802 |
| Removal of the Thrust-Reverser Harness (Multiplexer to Stow Switches) | AMM 78-33-06-000-803 |
| Installation of the Thrust-Reverser Harness (Multiplexer to Stow Switches) | AMM 78-33-06-400-803 |
Troubleshooting Recommendations:
- With the RH Throttle lever in the max reverse position, measure the continuity of the Right Reverse Idle and TR CMD switches on the Throttle Quadrant Assembly (TQA) as follow:
To From Expected Result Result A51J2 - W A51J2 - G < 1 Ω A51J4 - W A51J4 - G < 1 Ω - If the resistance value is good as per table above, continue with the next step.
- If there the resistance is out of tolerance, replace TQA. and do close out.
- MCID 1463 fault present, troubleshoot using the following steps for aircraft and engine fault isolation with reference to the Light Engine Maintenance Manual Subtask 72-00-00-810-294-A01.
