Failure of the HMU Torque Motor of the HPTCC Valve on Engine 1

TASK 75-21-00-810-805-A
Failure of the HMU Torque Motor of the HPTCC Valve on Engine 1

1. Possible Causes

2. Job Set-up Information
A. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP2011)	stoddard solvent

B. Referenced Information

REFERENCE	DESIGNATION
AMM 73-21-10-000-001	Removal of the Hydromechanical Unit (HMU)
AMM 73-21-10-000-002	Removal of the Hydromechanical Unit (HMU)
AMM 73-21-10-400-001	Installation of the Hydromechanical Unit (HMU)
AMM 73-21-10-400-002	Installation of the Hydromechanical Unit (HMU)
AMM 73-21-50-210-001	Visual Inspection of the Wiring Harness
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 75-21-10-000-001	Removal of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
AMM 75-21-10-000-002	Removal of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
AMM 75-21-10-400-001	Installation of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
AMM 75-21-10-400-002	Installation of the High Pressure Turbine Active Clearance Control (HPTACC) Valve

3. Fault Confirmation
Subtask 75-21-00-710-058-A ** ON A/C NOT FOR ALL

A. Do the operational test of the FADEC 1A on the ground (with engine motoring) AMM 73-29-00-710-040.

Subtask 75-21-00-710-058-B ** ON A/C NOT FOR ALL

A. Do the operational test of the FADEC 1A on the ground (with engine motoring) AMM 73-29-00-710-040.

4. Fault Isolation
Subtask 75-21-00-810-056-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message HPTC VLV (BLD), HMU:

replace the High Pressure Turbine Clearance Control (HPTCC) valve AMM 75-21-10-000-001 and AMM 75-21-10-400-001.

(1) If the fault continues:

(2) If the fault continues:

Subtask 75-21-00-810-056-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message HPTC VLV (BLD), HMU:

disconnect the CJ13 connector (TCC-A) from the TCC sensor (9 O'Clock).
visually examine the harness connector and sensor receptacle for damaged pins or contamination/oxidation.
if damage is found, repair or replace as required.
do a cleaning of the connector and receptacle using a bristle brush with stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
connect the harness connector to the sensor. Tighten the connector by hand plus one eighth of a turn. If necessary use soft nose pliers.

(1) If the fault continues:

replace the High Pressure Turbine Clearance Control (HPTCC) valve AMM 75-21-10-000-002 and AMM 75-21-10-400-002.

(2) If the fault continues:

(3) If the fault continues:

Subtask 75-21-00-710-059-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:37:01 UTC