High Idle Speed on both engines with Aircraft on Ground

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1. Possible Causes
· ZONE CONTROLLER ( 8HK )
· CONT-AIR COND SYSTEM 1 ( 47HH )
· CONT-AIR COND SYSTEM 2 ( 57HH )
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
Ref. AMM 21-61-34-000-002 Removal of the Air-Conditioning System Controller
Ref. AMM 21-61-34-400-002 Installation of the Air-Conditioning System Controller
Ref. AMM 21-63-34-000-001 Removal of the Zone Controller
Ref. AMM 21-63-34-400-001 Installation of the Zone Controller
Ref. AMM 71-00-00-710-043 Normal Engine Automatic Start Procedure
Ref. ASM 73-25-06
3. Fault Confirmation
Subtask 71-00-00-710-054-A
A. Not applicable, the fault is evident.
4. Fault Isolation
Subtask 71-00-00-810-054-A
A. If the fault symptom is identified by a high idle speed on both engines:
· replace the ZONE CONTROLLER ( 8HK ) Ref. AMM 21-63-34-000-001 and Ref.
AMM 21-63-34-400-001 .
(1) If the fault continues:
· do a check of the aircraft wiring between the CONT-ZONE TEMPERATURE (8HK) and both EIU
Ref. ASM 73-25-06:
(a) 8HK pins AA/1J, 2J to the first termina block.
(b) 8HK pins AA/1B, 2B to the first teminal block.
Subtask 71-00-00-810-054-B
A. If the fault symptom is identified by a high idle speed on both engines:
· replace the CONT-AIR COND SYSTEM 1 ( 47HH ) and CONT-AIR COND SYSTEM 2 ( 57HH ) Ref.
AMM 21-61-34-000-002 and Ref. AMM 21-61-34-400-002 .
(1) If the fault continues:
· do a check of the aircraft wiring between the ACSC (47HH, 57HH) and both EIU Ref. ASM
73-25-06:
(a) 57HH pins AA/7E, 7F to the first terminal block.
(b) 47HH pins AA/7E, 7F to the first terminal block.
Subtask 71-00-00-710-055-A
B. Test
(1) Start the engines Ref. AMM 71-00-00-710-043 .
(2) Check that the idle speed is correct. [Rev.6 from Feb 2017] 2026.04.04 04:35:00 UTC