Loss of the T3 Thermocouple Signal - Engine 1 - Channel A
TASK 77-20-00-810-809-A
Loss of the T3 Thermocouple Signal - Engine 1 - Channel A
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 77-20-00-710-066-A ** ON A/C NOT FOR ALL
Subtask 77-20-00-810-058-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:37:44 UTC
Loss of the T3 Thermocouple Signal - Engine 1 - Channel A
1. Possible Causes
- T3 thermocouple
- CJ13 harness
- J13 harness
- ECU [4000KS]
- HJ13 harness
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 73-21-50-000-005 | Removal of the CJ13 Harness |
| AMM 73-21-50-000-012 | Removal of the J13 Harness |
| AMM 73-21-50-000-029 | Removal of the CJ13 Harness |
| AMM 73-21-50-000-046 | Removal of the HJ13 Harness for SAC Engines |
| AMM 73-21-50-210-001 | Visual Inspection of the Wiring Harness |
| AMM 73-21-50-210-002 | Visual Inspection of the Wiring Harnesses |
| AMM 73-21-50-400-005 | Installation of the CJ13 Harness |
| AMM 73-21-50-400-012 | Installation of the J13 Harness |
| AMM 73-21-50-400-029 | Installation of the CJ13 Harness |
| AMM 73-21-50-400-046 | Installation of the HJ13 Harness for SAC Engines |
| AMM 73-21-60-000-001 | Removal of the Electronic Control Unit (ECU) |
| AMM 73-21-60-400-001 | Installation of the Electronic Control Unit (ECU) |
| AMM 73-29-00-710-040 | Operational Test of the FADEC on the ground (with Engine Motoring) |
| AMM 77-23-10-000-001 | Removal of the Compressor Discharge Temperature (T3) Sensor |
| AMM 77-23-10-000-002 | Removal of the Compressor Discharge Temperature (T3) Sensor |
| AMM 77-23-10-400-001 | Installation of the Compressor Discharge Temperature (T3) Sensor |
| AMM 77-23-10-400-002 | Installation of the Compressor Discharge Temperature (T3) Sensor |
Subtask 77-20-00-710-066-A ** ON A/C NOT FOR ALL
A. Test
(1) Do the operational test of the FADEC 1A on the ground (with engine non motoring) AMM 73-29-00-710-040.
Subtask 77-20-00-710-066-B ** ON A/C NOT FOR ALL (1) Do the operational test of the FADEC 1A on the ground (with engine non motoring) AMM 73-29-00-710-040.
A. Test
(1) Do the operational test of the FADEC 1A on the ground (with engine non motoring) AMM 73-29-00-710-040.
4. Fault Isolation(1) Do the operational test of the FADEC 1A on the ground (with engine non motoring) AMM 73-29-00-710-040.
Subtask 77-20-00-810-058-A ** ON A/C NOT FOR ALL
A. The failure message is generated if channel A sensor signal is invalid or out of range.
Subtask 77-20-00-810-058-B ** ON A/C NOT FOR ALL NOTE: If T3 sensor Part Number is 1348M21P01, P04 or P05, replace T3 sensor AMM 77-23-10-000-001 and AMM 77-23-10-400-001.
(1) If the failure message T3 SENS, J13, ECU is not confirmed: - no maintenance action is required.
- visually examine the T3 thermocouple receptacle and the CJ13 harness connector for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- visually examine the ECU (4000KS) receptacle and the J13 harness connector for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- replace the T3 thermocouple AMM 77-23-10-000-001 and AMM 77-23-10-400-001.
- replace the CJ13 harness AMM 73-21-50-000-005 and AMM 73-21-50-400-005.
- replace the J13 harness AMM 73-21-50-000-012 and AMM 73-21-50-400-012.
- replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- disconnect the two CJ13 connectors from the T3 thermocouple
- visually examine the T3 thermocouple receptacle and the CJ13 harness connectors for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- do a resistance check of the two T3 thermocouple connectors between:
. pins A and B (0.5 to 10 ohms)
. pin A and the ground (> 10 megohms).
- replace the T3 thermocouple AMM 77-23-10-000-001 and AMM 77-23-10-400-001.
- reconnect the CJ13 harness to the T3 thermocouple
- disconnect the J13 harness from the ECU
- visually examine the ECU (4000KS) receptacle and the J13 harness connector for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- do an electrical resistance test through the J13 harness between:
. pins 4 and 5 (0.5 to 10 ohms)
. pins 14 and 15 (0.5 to 10 ohms)
. pins 4 and 16 (> 10 megohms)
. pins 14 and 16 (> 10 megohms)
. pin 4 and the ground (> 10 megohms)
. pin 14 and the ground (> 10 megohms).
- replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- reconnect the J13 harness
- disconnect the J13 harness from the CJ13 harness at the 6 o'clock junction box
- do an electrical resistance test through the CJ13 harness between:
. pins 7 and 8 (0.5 to 10 ohms)
. pins 1 and 10 (0.5 to 10 ohms)
. pins 7 and 9 (> 10 megohms)
. pins 1 and 9 (> 10 megohms)
. pin 7 and the ground (> 10 megohms)
. pin 1 and the ground (> 10 megohms).
- replace the CJ13 harness AMM 73-21-50-000-005 and AMM 73-21-50-400-005.
- replace the J13 harness AMM 73-21-50-000-012 and AMM 73-21-50-400-012.
A. The failure message is generated if channel A sensor signal is invalid or out of range.
Subtask 77-20-00-810-058-C ** ON A/C NOT FOR ALL NOTE: If T3 sensor Part Number is 1348M21P01, P04 or P05, replace T3 sensor AMM 77-23-10-000-001 and AMM 77-23-10-400-001.
(1) If the failure message T3 SNSR, J13, ECU is not confirmed: - no maintenance action is required.
- visually examine the T3 thermocouple receptacle and the CJ13 harness connector for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- visually examine the ECU (4000KS) receptacle and the J13 harness connector for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- replace the T3 thermocouple AMM 77-23-10-000-001 and AMM 77-23-10-400-001.
- replace the CJ13 harness AMM 73-21-50-000-005 and AMM 73-21-50-400-005.
- replace the J13 harness AMM 73-21-50-000-012 and AMM 73-21-50-400-012.
- replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- disconnect the two CJ13 connectors from the T3 thermocouple
- visually examine the T3 thermocouple receptacle and the CJ13 harness connectors for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- do a resistance check of the two T3 thermocouple connectors between:
. pins A and B (0.5 to 10 ohms)
. pin A and the ground (> 10 megohms).
- replace the T3 thermocouple AMM 77-23-10-000-001 and AMM 77-23-10-400-001.
- reconnect the CJ13 harness to the T3 thermocouple
- disconnect the J13 harness from the ECU
- visually examine the ECU (4000KS) receptacle and the J13 harness connector for damaged pins and contamination AMM 73-21-50-210-001.
- repair or replace as required.
- do an electrical resistance test through the J13 harness between:
. pins 4 and 5 (0.5 to 10 ohms)
. pins 14 and 15 (0.5 to 10 ohms)
. pins 4 and 16 (> 10 megohms)
. pins 14 and 16 (> 10 megohms)
. pin 4 and the ground (> 10 megohms)
. pin 14 and the ground (> 10 megohms).
- replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- reconnect the J13 harness
- disconnect the J13 harness from the CJ13 harness at the 6 o'clock junction box
- do an electrical resistance test through the CJ13 harness between:
. pins 7 and 8 (0.5 to 10 ohms)
. pins 1 and 10 (0.5 to 10 ohms)
. pins 7 and 9 (> 10 megohms)
. pins 1 and 9 (> 10 megohms)
. pin 7 and the ground (> 10 megohms)
. pin 1 and the ground (> 10 megohms).
- replace the CJ13 harness AMM 73-21-50-000-005 and AMM 73-21-50-400-005.
- replace the J13 harness AMM 73-21-50-000-012 and AMM 73-21-50-400-012.
A. The failure message is generated if channel A sensor signal is invalid or out of range.
Subtask 77-20-00-710-067-A ** ON A/C NOT FOR ALL NOTE: If T3 sensor Part Number is 1348M21P01, P04 or P05, replace T3 sensor AMM 77-23-10-000-002 and AMM 77-23-10-400-002.
(1) If the failure message T3 SNSR, J13, ECU is not confirmed: - no maintenance action is required.
- visually examine the T3 thermocouple receptacle and the CJ13 harness connector for damaged pins and contamination AMM 73-21-50-210-002.
- repair or replace as required.
- visually examine the ECU (4000KS) receptacle and the HJ13 harness connector for damaged pins and contamination AMM 73-21-50-210-002.
- repair or replace as required.
- replace the T3 thermocouple AMM 77-23-10-000-002 and AMM 77-23-10-400-002.
- replace the CJ13 harness AMM 73-21-50-000-029 and AMM 73-21-50-400-029.
- replace the HJ13 harness AMM 73-21-50-000-046 and AMM 73-21-50-400-046.
- replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- disconnect the two CJ13 connectors from the T3 thermocouple
- visually examine the T3 thermocouple receptacle and the CJ13 harness connectors for damaged pins and contamination AMM 73-21-50-210-002.
- repair or replace as required.
- do a resistance check of the two T3 thermocouple connectors between:
. pins A and B (0.5 to 10 ohms)
. pin A and the ground (> 10 megohms).
- replace the T3 thermocouple AMM 77-23-10-000-002 and AMM 77-23-10-400-002.
- reconnect the CJ13 harness to the T3 thermocouple
- disconnect the HJ13 harness from the ECU
- visually examine the ECU (4000KS) receptacle and the HJ13 harness connector for damaged pins and contamination AMM 73-21-50-210-002.
- repair or replace as required.
- do an electrical resistance test through the HJ13 harness between:
. pins 4 and 5 (0.5 to 10 ohms)
. pins 14 and 15 (0.5 to 10 ohms)
. pins 4 and 16 (> 10 megohms)
. pins 14 and 16 (> 10 megohms)
. pin 4 and the ground (> 10 megohms)
. pin 14 and the ground (> 10 megohms).
- replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- reconnect the HJ13 harness
- disconnect the HJ13 harness from the CJ13 harness at the 6 o'clock junction box
- do an electrical resistance test through the CJ13 harness between:
. pins 7 and 8 (0.5 to 10 ohms)
. pins 1 and 10 (0.5 to 10 ohms)
. pins 7 and 9 (> 10 megohms)
. pins 1 and 9 (> 10 megohms)
. pin 7 and the ground (> 10 megohms)
. pin 1 and the ground (> 10 megohms).
- replace the CJ13 harness AMM 73-21-50-000-029 and AMM 73-21-50-400-029.
- replace the HJ13 harness AMM 73-21-50-000-046 and AMM 73-21-50-400-046.
B. Do the test given in Para. 3.A.
(1) No additional maintenance action is required if the fault is not confirmed.
(2) Repeat the fault isolation procedure if the fault continues.
(1) No additional maintenance action is required if the fault is not confirmed.
(2) Repeat the fault isolation procedure if the fault continues.