Loss of T25 Sensor Signal through the Two Channels on Engine 1
TASK 73-20-00-810-857-A
Loss of T25 Sensor Signal through the Two Channels on Engine 1
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Referenced Information
3. Fault Confirmation
Subtask 73-20-00-710-130-A ** ON A/C NOT FOR ALL
Subtask 73-20-00-810-107-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:41:00 UTC
Loss of T25 Sensor Signal through the Two Channels on Engine 1
1. Possible Causes
- ECU [4000KS]
- harness J11
- harness J12
- harness CJ11R
- harness CJ12R
- engine 1 T25 temperature sensor
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | BRUSH - BRISTLED |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.CP2011) | stoddard solvent |
| REFERENCE | DESIGNATION |
|---|---|
| AMM 73-21-20-000-001 | Removal of the T25 Temperature Sensor |
| AMM 73-21-20-000-002 | Removal of the T25 Temperature Sensor |
| AMM 73-21-20-400-001 | Installation of the T25 Temperature Sensor |
| AMM 73-21-20-400-002 | Installation of the T25 Temperature Sensor |
| AMM 73-21-50-000-002 | Removal of the CJ11R Harness |
| AMM 73-21-50-000-004 | Removal of the CJ12R Harness |
| AMM 73-21-50-000-010 | Removal of the J11 Harness |
| AMM 73-21-50-000-011 | Removal of the J12 Harness |
| AMM 73-21-50-000-026 | Removal of the CJ11R Harness for SAC Engines |
| AMM 73-21-50-000-028 | Removal of the CJ12R Harness for SAC Engines |
| AMM 73-21-50-000-044 | Removal of the HJ11 Harness for SAC Engines |
| AMM 73-21-50-000-045 | Removal of the HJ12 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 73-21-50-400-002 | Installation of the CJ11R Harness |
| AMM 73-21-50-400-004 | Installation of the CJ12R Harness |
| AMM 73-21-50-400-010 | Installation of the J11 Harness |
| AMM 73-21-50-400-011 | Installation of the J12 Harness |
| AMM 73-21-50-400-026 | Installation of the CJ11R Harness for SAC Engines |
| AMM 73-21-50-400-028 | Installation of the CJ12R Harness for SAC Engines |
| AMM 73-21-50-400-044 | Installation of the HJ11 Harness for SAC Engines |
| AMM 73-21-50-400-045 | Installation of the HJ12 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) |
Subtask 73-20-00-710-130-A ** ON A/C NOT FOR ALL
A. Do the operational test of the FADEC 1A and 1B on the ground (withe engine non motoring) AMM 73-29-00-710-040.
4. Fault IsolationSubtask 73-20-00-810-107-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance messages T25 SENS, J11, ECU + T25 SENS, J12, ECU:
Subtask 73-20-00-810-107-B ** ON A/C NOT FOR ALL - do a check for open or short to ground of the harnesses J11 and J12 between the ECU (4000KS) and the 6 o'clock junction box, between the 6 o'clock junction box and the T25 temperature sensor pins J11 and J12/19, 37, 38 to pins J11 and J12/1, 2, 3.
- repair the defective above wirings.
- disconnect the harnesses J11 and J12 from the ECU (4000KS).
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
- do a check of each ECU cable resistance between:
. pins 37 and 38 (160 to 250 Ohms)
. pins 37 and 19 (> 10 Megohms)
. pin 37 and ground (> 10 Megohms)
- replace the ECU [4000KS] AMM 73-21-60-000-001 AMM 73-21-60-400-001.
- disconnect the harnesses CJ11 and CJ12 at 6 o'clock junction box.
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
- do a check of the resistance cables CJ11R and CJ12R between:
for cable CJ11R
. pins 25 and 26 (160 to 250 Ohms)
. pins 25 and 13 (> 10 Megohms)
. pin 25 and ground (> 10 Megohms)
for cable CJ12R
. pins 15 and 16 (160 to 250 Ohms)
. pins 15 and 13 (> 10 Megohms)
. pin 15 and ground (> 10 Megohms)
- replace the defective harness J11 AMM 73-21-50-000-010 AMM 73-21-50-400-010 or
- replace the defective harness J12 AMM 73-21-50-000-011 AMM 73-21-50-400-011.
- disconnect the harnesses CJ11R and CJ12R at T25 sensor.
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
- do a check of the T25 sensor resistance between:
for cable CJ11R
. pins 1 and 2 (160 to 250 Ohms)
. pin 1 and ground (> 10 Megohms)
for cable CJ12R
. pins 1 and 2 (160 to 250 Ohms)
. pin 1 and ground (> 10 Megohms)
- replace the defective harness CJ11R AMM 73-21-50-000-002 AMM 73-21-50-400-002 or
- replace the defective harness CJ12R AMM 73-21-50-000-004 AMM 73-21-50-400-004.
- replace the engine 1 T25 temperature sensor AMM 73-21-20-000-001 AMM 73-21-20-400-001.
A. If the test gives the maintenance messages T25 SNSR, J11, ECU + T25 SNSR, J12, ECU:
Subtask 73-20-00-810-107-C ** ON A/C NOT FOR ALL - do a check for open or short to ground of the harnesses J11 and J12 between the ECU (4000KS) and the 6 o'clock junction box, between the 6 o'clock junction box and the T25 temperature sensor pins J11 and J12/19, 37, 38 to pins J11 and J12/1, 2, 3.
- repair the defective above wirings.
- disconnect the harnesses J11 and J12 from the ECU (4000KS).
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
- do a check of each ECU cable resistance between:
. pins 37 and 38 (160 to 250 Ohms)
. pins 37 and 19 (> 10 Megohms)
. pin 37 and ground (> 10 Megohms)
- replace the ECU [4000KS] AMM 73-21-60-000-001 AMM 73-21-60-400-001.
- disconnect the harnesses CJ11 and CJ12 at 6 o'clock junction box.
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
- do a check of the resistance cables CJ11R and CJ12R between:
for cable CJ11R
. pins 25 and 26 (160 to 250 Ohms)
. pins 25 and 13 (> 10 Megohms)
. pin 25 and ground (> 10 Megohms)
for cable CJ12R
. pins 15 and 16 (160 to 250 Ohms)
. pins 15 and 13 (> 10 Megohms)
. pin 15 and ground (> 10 Megohms)
- replace the defective harness J11 AMM 73-21-50-000-010 AMM 73-21-50-400-010 or
- replace the defective harness J12 AMM 73-21-50-000-011 AMM 73-21-50-400-011.
- disconnect the harnesses CJ11R and CJ12R at T25 sensor.
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
- do a check of the T25 sensor resistance between:
for cable CJ11R
. pins 1 and 2 (160 to 250 Ohms)
. pin 1 and ground (> 10 Megohms)
for cable CJ12R
. pins 1 and 2 (160 to 250 Ohms)
. pin 1 and ground (> 10 Megohms)
- replace the defective harness CJ11R AMM 73-21-50-000-002 AMM 73-21-50-400-002 or
- replace the defective harness CJ12R AMM 73-21-50-000-004 AMM 73-21-50-400-004.
- replace the engine 1 T25 temperature sensor AMM 73-21-20-000-001 AMM 73-21-20-400-001.
A. If the test gives the maintenance messages T25 SNSR, J11, ECU + T25 SNSR, J12, ECU:
Subtask 73-20-00-710-131-A ** ON A/C NOT FOR ALL - do a check for open or short to ground of the harnesses J11 and J12 between the ECU (4000KS) and the 6 o'clock junction box, between the 6 o'clock junction box and the T25 temperature sensor pins J11 and J12/19, 37, 38 to pins J11 and J12/1, 2, 3.
- repair the defective above wirings.
- disconnect the harnesses J11 and J12 from the ECU (4000KS).
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-002.
- do a check of each ECU cable resistance between:
. pins 37 and 38 (160 to 250 Ohms)
. pins 37 and 19 (> 10 Megohms)
. pin 37 and ground (> 10 Megohms)
- replace the ECU [4000KS] AMM 73-21-60-000-001 AMM 73-21-60-400-001.
- disconnect the harnesses CJ11 and CJ12 at 6 o'clock junction box.
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-002.
- do a check of the resistance cables CJ11R and CJ12R between:
for cable CJ11R
. pins 25 and 26 (160 to 250 Ohms)
. pins 25 and 13 (> 10 Megohms)
. pin 25 and ground (> 10 Megohms)
for cable CJ12R
. pins 15 and 16 (160 to 250 Ohms)
. pins 15 and 13 (> 10 Megohms)
. pin 15 and ground (> 10 Megohms)
- replace the defective harness J11 AMM 73-21-50-000-044 AMM 73-21-50-400-044 or
- replace the defective harness J12 AMM 73-21-50-000-045 AMM 73-21-50-400-045.
- disconnect the harnesses CJ11R and CJ12R at T25 sensor.
- do a visual inspection of the harness connector and receptacle. Look for contamination or oxidation or pins that have damage.
- if you find damage, repair or replace as required.
- clean the connector and receptacle with a BRUSH - BRISTLED and stoddard solvent (Material No.CP2011) AMM 73-21-50-210-002.
- do a check of the T25 sensor resistance between:
for cable CJ11R
. pins 1 and 2 (160 to 250 Ohms)
. pin 1 and ground (> 10 Megohms)
for cable CJ12R
. pins 1 and 2 (160 to 250 Ohms)
. pin 1 and ground (> 10 Megohms)
- replace the defective harness CJ11R AMM 73-21-50-000-026 AMM 73-21-50-400-026 or
- replace the defective harness CJ12R AMM 73-21-50-000-028 AMM 73-21-50-400-028.
- replace the engine 1 T25 temperature sensor AMM 73-21-20-000-002 AMM 73-21-20-400-002.
B. Do the test given in Para. 3.A.