01/03/25
Message Overview:
Message Description:
Right engine TT2 sensor/heater fault 4.
[MCID 0805]
TT2 Sensor/Heater 4.
Detection of a fault primarily in the TT2 sensor/heater.
Possible Causes:
- Wiring Harness (W1)
- Wiring Harness (W6)
- TT2 Current Sense Relay in the DC Power Center (DCPC)
- TT2 Sensor
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
- If the L or R ENGINE FAULT CAS message is shown with this fault, this is a No Dispatch condition.
- If there isn't a L or R ENGINE FAULT CAS message, only a MCID or fault equation, then this is a Long Term Dispatch (LT) fault and is subject to correction outlined in the Honeywell LEMM SUBTASK 5-10-00-200-003.
- Check for the following MDC messages displayed with the fault: X-channel bus 1A (MCID 0905), X-channel bus 1B (MCID 0906), X-channel discrete 1A (MCID 0933), X-channel discrete 1B (MCID 0934). If any of the above MCID codes are posted, correct the cross channel faults first.
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 |
| Remove the Electrical Power from the Aircraft | AMM 24-00-00-861-802 |
| Removal of the DC Power Center (DCPC) | AMM 24-61-01-000-801 |
| Installation of the DC Power Center (DCPC) | AMM 24-61-01-400-801 |
| Functional Test of the DC Power Center (DCPC) | AMM 24-61-01-720-801 |
| Operational Test of the Nacelle Anti-Ice System | AMM 30-21-00-710-801 |
| General Visual Inspection of the Engine Wiring Harness | AMM 71-50-00-210-802 |
Troubleshooting Recommendations:
Check MCID for faults, if a 805 is listed, troubleshoot using the following steps for aircraft and engine fault isolation with reference to the Light Engine Maintenance Manual TASK 72-00-00-810-113.
- Check and reset Circuit Breaker CB2-E11.
- Check & verify the system operation IAW AMM TASK 30-21-00-710-801, look for the system fault by viewing the ANTI-ICE synoptic page looking for the amber T2 fault. If the fault still exists, continue, otherwise closeout.
- Check the TT2 probe heater for continuity, check resistance from the Right DC Power Center A35P3 pin 52 to ground, there should be continuity ≈ 5 to 30Ω. Replace TT2 sensor if out of tolerance per the Honeywell LEMM.
- If there is not continuity, gain access to the following connectors, inspect for damage, then check the following segments per the table, repair wiring if required per the wiring manual standard practices:
From To Value TT2 Sensor Pin 5 TT2 Sensor Pin 6 ≈ 5 to 30Ω W6P7 Pin 6 Ground <.01Ω W6P7 Pin 5 A36P3 Pin 52 <.01Ω - With a meter, verify and ring the TT2 sense output from the Right DC Power Center to the ECU Channel A & B.
From To Value A36P6 Pin 8 W1P2/A42J1 Pin 63 <.01Ω A36P3 Pin 33 W2P2/A40J1 Pin 63 <.01Ω - If the wiring checks good, remove and replace the DC power center PCB1 protection card IAW AMM TASK 24-61-77-000-801, TASK 24-61-77-400-801. Recheck the system IAW AMM TASK 30-21-00-710-801.
