Loss of the Feedback Signals from the LPTC Valve - Engine 2 - Channel A and Channel B
TASK 75-22-00-810-808-A
Loss of the Feedback Signals from the LPTC Valve - Engine 2 - Channel A and Channel B
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 75-22-00-710-063-A ** ON A/C NOT FOR ALL
Subtask 75-22-00-810-059-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:37:03 UTC
Loss of the Feedback Signals from the LPTC Valve - Engine 2 - Channel A and Channel B
1. Possible Causes
- LPTC valve
- ECU [4000KS]
- harness J11
- harness CJ11R
- harness J12
- harness CJ12R
- harness HJ11
- harness HJ12
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| 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) |
| AMM 75-22-10-000-001 | Removal of the Low Pressure Turbine Active Clearance Control Valve (LPTACC). |
| AMM 75-22-10-000-002 | Removal of the Low Pressure Turbine Active Clearance Control (LPTACC) Valve |
| AMM 75-22-10-400-001 | Installation of the Low Pressure Turbine Active Clearance Control Valve (LPTACC). |
| AMM 75-22-10-400-002 | Installation of the Low Pressure Turbine Active Clearance Control (LPTACC) Valve |
Subtask 75-22-00-710-063-A ** ON A/C NOT FOR ALL
A. Test
(1) Do the operational test of the FADEC 2A and 2B on the ground (with engine motoring) AMM 73-29-00-710-040.
4. Fault Isolation(1) Do the operational test of the FADEC 2A and 2B on the ground (with engine motoring) AMM 73-29-00-710-040.
Subtask 75-22-00-810-059-A ** ON A/C NOT FOR ALL
A. The failure messages are generated if the channels A and B signals are invalid, out of range, or if both channels disagree.
(1) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed:
(a) No maintenance action is required.
(2) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed but are repetitive:
Subtask 75-22-00-810-059-C ** ON A/C NOT FOR ALL (1) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed:
(a) No maintenance action is required.
(2) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed but are repetitive:
- Disconnect the CJ11R and CJ12R harnesses from the LPTC valve (LPT-A and LPT-B connectors) and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
- Repair or replace as required.
- Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
- Replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- Replace the harness J11 AMM 73-21-50-000-010 and AMM 73-21-50-400-010.
- Replace the harness CJ11R (located in the right core compartment) AMM 73-21-50-000-002 AMM 73-21-50-400-002.
- Replace the harness J12 AMM 73-21-50-000-011 and AMM 73-21-50-400-011.
- Replace the harness CJ12R (located in the right core compartment) AMM 73-21-50-000-004 AMM 73-21-50-400-004.
- Disconnect the CJ11R harness (LPT-A) connector (located in the right core compartment) from the LPTC valve and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
- Repair or replace as required.
- Do the electrical resistance test through the LPTC valve between:
. Pins 2 and 3 (80 to 109.5 ohms)
. Pins 4 and 5 (85 to 115 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pin 2 and the ground (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms).
- Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
- Connect the CJ11R harness (LPT-A) connector to the LPTC valve receptacle (located in the right core compartment),
- Disconnect the J11 harness from the ECU (4000KS) and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
- Repair or replace as required.
- Do an electrical resistance test through the J11 harness between:
. Pins 4 and 5 (80 to 109.5 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pins 2 and 3 (85 to 115 ohms)
. Pins 4 and 1 (> 10 megohms)
. Pins 6 and 1 (> 10 megohms)
. Pins 2 and 1 (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- Disconnect the J11 harness from the CJ11R harness located at the 6 o'clock junction box and do an electrical resistance test through the CJ11R harness between:
. Pins 20 and 21 (80 to 109.5 ohms)
. Pins 7 and 19 (85 to 115 ohms)
. Pins 2 and 9 (85 to 115 ohms)
. Pins 20 and 8 (> 10 megohms)
. Pins 7 and 8 (> 10 megohms)
. Pins 2 and 8 (> 10 megohms)
. Pin 20 and the ground (> 10 megohms)
. Pin 7 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the harness J11 (from the ECU to the 6 o'clock junction box) AMM 73-21-50-000-010 and AMM 73-21-50-400-010.
- Replace the harness CJ11R AMM 73-21-50-000-002 and AMM 73-21-50-400-002.
- Disconnect the CJ12R harness (LPT-B) connector (located in the right core compartment) from the LPTC valve and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
- Repair or replace as required.
- Do the electrical resistance test through the LPTC valve between:
. Pins 2 and 3 (80 to 109.5 ohms)
. Pins 4 and 5 (85 to 115 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pin 2 and the ground (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms).
- Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
- Connect the CJ12R harness (LPT-B) connector to the LPTC valve receptacle (located in the right core compartment),
- Disconnect the harness J12 from the ECU (4000KS) and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
- Repair or replace as required.
- Do an electrical resistance test through the J12 harness between:
. Pins 4 and 5 (80 to 109.5 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pins 2 and 3 (85 to 115 ohms)
. Pins 4 and 1 (> 10 megohms)
. Pins 6 and 1 (> 10 megohms)
. Pins 2 and 1 (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- Disconnect the J12 harness from the CJ12R harness located at the 6 o'clock junction box and do an electrical resistance test through the CJ12R harness between:
. Pins 14 and 13 (80 to 109.5 ohms)
. Pins 12 and 3 (85 to 115 ohms)
. Pins 2 and 1 (85 to 115 ohms)
. Pins 14 and 4 (> 10 megohms)
. Pins 12 and 4 (> 10 megohms)
. Pins 2 and 4 (> 10 megohms)
. Pin 14 and the ground (> 10 megohms)
. Pin 12 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the harness J12 (from the ECU to the 6 o'clock junction box) AMM 73-21-50-000-011 and AMM 73-21-50-400-011.
- Replace the harness CJ12R AMM 73-21-50-000-004 and AMM 73-21-50-400-004.
A. The failure messages are generated if the channels A and B signals are invalid, out of range, or if both channels disagree.
(1) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed:
(a) No maintenance action is required.
(2) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed but are repetitive:
Subtask 75-22-00-710-069-A ** ON A/C NOT FOR ALL (1) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed:
(a) No maintenance action is required.
(2) If the failure messages LPTC VLV, J11, ECU and LPTC VLV, J12, ECU are not confirmed but are repetitive:
- Disconnect the CJ11R and CJ12R harnesses from the LPTC valve (LPT-A and LPT-B connectors) and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
- Repair or replace as required.
- Replace the LPTC valve AMM 75-22-10-000-002 and AMM 75-22-10-400-002.
- Replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- Replace the harness HJ11 AMM 73-21-50-000-044 and AMM 73-21-50-400-044.
- Replace the harness CJ11R (located in the right core compartment) AMM 73-21-50-000-026 AMM 73-21-50-400-026.
- Replace the harness HJ12 AMM 73-21-50-000-045 and AMM 73-21-50-400-045.
- Replace the harness CJ12R (located in the right core compartment) AMM 73-21-50-000-028 AMM 73-21-50-400-028.
- Disconnect the CJ11R harness (LPT-A) connector (located in the right core compartment) from the LPTC valve and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
- Repair or replace as required.
- Do the electrical resistance test through the LPTC valve between:
. Pins 2 and 3 (80 to 109.5 ohms)
. Pins 4 and 5 (85 to 115 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pin 2 and the ground (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms).
- Replace the LPTC valve AMM 75-22-10-000-002 and AMM 75-22-10-400-002.
- Connect the CJ11R harness (LPT-A) connector to the LPTC valve receptacle (located in the right core compartment),
- Disconnect the HJ11 harness from the ECU (4000KS) and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
- Repair or replace as required.
- Do an electrical resistance test through the HJ11 harness between:
. Pins 4 and 5 (80 to 109.5 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pins 2 and 3 (85 to 115 ohms)
. Pins 4 and 1 (> 10 megohms)
. Pins 6 and 1 (> 10 megohms)
. Pins 2 and 1 (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- Disconnect the HJ11 harness from the CJ11R harness located at the 6 o'clock junction box and do an electrical resistance test through the CJ11R harness between:
. Pins 20 and 21 (80 to 109.5 ohms)
. Pins 7 and 19 (85 to 115 ohms)
. Pins 2 and 9 (85 to 115 ohms)
. Pins 20 and 8 (> 10 megohms)
. Pins 7 and 8 (> 10 megohms)
. Pins 2 and 8 (> 10 megohms)
. Pin 20 and the ground (> 10 megohms)
. Pin 7 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the harness HJ11 (from the ECU to the 6 o'clock junction box) AMM 73-21-50-000-044 and AMM 73-21-50-400-044.
- Replace the harness CJ11R AMM 73-21-50-000-026 and AMM 73-21-50-400-026.
- Disconnect the CJ12R harness (LPT-B) connector (located in the right core compartment) from the LPTC valve and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
- Repair or replace as required.
- Do the electrical resistance test through the LPTC valve between:
. Pins 2 and 3 (80 to 109.5 ohms)
. Pins 4 and 5 (85 to 115 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pin 2 and the ground (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms).
- Replace the LPTC valve AMM 75-22-10-000-002 and AMM 75-22-10-400-002.
- Connect the CJ12R harness (LPT-B) connector to the LPTC valve receptacle (located in the right core compartment),
- Disconnect the HJ12 harness from the ECU (4000KS) and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
- Repair or replace as required.
- Do an electrical resistance test through the HJ12 harness between:
. Pins 4 and 5 (80 to 109.5 ohms)
. Pins 6 and 7 (85 to 115 ohms)
. Pins 2 and 3 (85 to 115 ohms)
. Pins 4 and 1 (> 10 megohms)
. Pins 6 and 1 (> 10 megohms)
. Pins 2 and 1 (> 10 megohms)
. Pin 4 and the ground (> 10 megohms)
. Pin 6 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- Disconnect the HJ12 harness from the CJ12R harness located at the 6 o'clock junction box and do an electrical resistance test through the CJ12R harness between:
. Pins 14 and 13 (80 to 109.5 ohms)
. Pins 12 and 3 (85 to 115 ohms)
. Pins 2 and 1 (85 to 115 ohms)
. Pins 14 and 4 (> 10 megohms)
. Pins 12 and 4 (> 10 megohms)
. Pins 2 and 4 (> 10 megohms)
. Pin 14 and the ground (> 10 megohms)
. Pin 12 and the ground (> 10 megohms)
. Pin 2 and the ground (> 10 megohms).
- Replace the harness HJ12 (from the ECU to the 6 o'clock junction box) AMM 73-21-50-000-045 and AMM 73-21-50-400-045.
- Replace the harness CJ12R AMM 73-21-50-000-028 and AMM 73-21-50-400-028.
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.