NAI Thermocouple Temperature On Channels A and B Disagreement

TASK 30-21-00-810-823-A
NAI Thermocouple Temperature On Channels A and B Disagreement

1. Possible Causes

THERMOCOUPLE ASSEMBLY, OVERHEAT INDICATION, FAN CASE [4160KS]
W04 HARNESS [4088KS]
W03 HARNESS [4087KS]
[4000KS]

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	PLIERS - JAWED, SOFT

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 71-00-00-810-835-A	Component and Harness Intermittent Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults
AMM 30-21-24-000-801	Removal of the Nacelle Anti-Ice Fan Case Thermocouple
AMM 30-21-24-400-801	Installation of the Nacelle Anti-Ice Fan Case Thermocouple
AMM 71-13-00-010-802	Opening of the Fan Cowl Doors
AMM 71-13-00-410-802	Closing of the Fan Cowl Doors
AWM 715134
AMM 73-21-00-710-806	Test No.7 - EEC Operation Test (Self Test)
AMM 73-21-01-000-801	Removal of the Electronic Engine Control (EEC)
AMM 73-21-01-400-801	Installation of the Electronic Engine Control (EEC)
AMM 73-21-63-000-802	Removal of the Electronic Engine Control (EEC) Wiring Harness (W03)
AMM 73-21-63-400-802	Installation of the Electronic Engine Control (EEC) Wiring Harness (W03)
AMM 73-21-64-000-802	Removal of the Electronic Engine Control (EEC) Wiring Harness (W04)
AMM 73-21-64-400-802	Installation of the Electronic Engine Control (EEC) Wiring Harness (W04)

3. Fault Confirmation
Subtask 30-21-00-730-060-A ** ON A/C NOT FOR ALL

A. Test
Do the EEC system test AMM 73-21-00-710-806.
(1) If the maintenance message does not come into view again, do the component and harness intermittent for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).
(a) If you find no fault, send the engine back to service and monitor the engine to make sure that the maintenance message does not come into view again.
(2) If the maintenance message comes into view again (hard fault) for Channels A and B, go to the Para. Fault Isolation.

4. Fault Isolation

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

CAUTION: MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.

Subtask 30-21-00-810-072-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Open the fan cowl-doors AMM 71-13-00-010-802.
(2) Make sure that electrical connector 4113VC-A of the NAI fan-case thermocouple is correctly engaged in the socket of the fan case harness.
(a) If it is not correctly engaged, engage it.

Do the test given in Para. 3.

(3) If the fault continues, disconnect the electrical connector 4113VC-A and do a visual inspection of the electrical connector 4113VC-A and of the receptacle of the NAI fan-case thermocouple for bent pins, contamination or corrosion or visual signs of damage.
(a) If you find damage on electrical connector 4113VC-A:

Replace the THERMOCOUPLE ASSEMBLY, OVERHEAT INDICATION, FAN CASE [4160KS] AMM 30-21-24-000-801 and AMM 30-21-24-400-801.
Do the test given in Para. 3.

(b) If you find no damage on electrical connector 4113VC-A or on the receptacle:

Do a resistance check AWM 715134 between:
.Pin 4113VCA/4 and pin 4113VCA/12 of the fan-case overheat-indication thermocouple-assembly.
.Pin 4113VCA/6 and pin 4113VCA/7 of the fan-case overheat-indication thermocouple-assembly.

1 If the resistance is more than 250 ohm:

Replace the THERMOCOUPLE ASSEMBLY, OVERHEAT INDICATION, FAN CASE [4160KS] AMM 30-21-24-000-801 and AMM 30-21-24-400-801.
Do the test given in Para. 3.

2 If the resistance is less than 250 ohm:

Use PLIERS - JAWED, SOFT to disconnect electrical connector P13 of the EEC.
Do a visual inspection on the electrical connector P13 of the EEC for bent pins, contamination, corrosion or visual signs of damage.

a If you find damage on electrical connector P13:

Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
Do the test given in Para. 3.

b If there is no damage or if fault continues, do a continuity check AWM 715134 of the WO4 harness between:
.Pin P13/m of the EEC and pin 12 of 4113VC
.Pin P13/k of the EEC and pin 4 of 4113VC
.Pin J107/42 of 4101VC and pin 7 of 4113VC
.Pin J107/43 of 4101VC and pin 6 of 4113VC.
c If there is no continuity:

Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
Do the test given in Para. 3.

d If there is continuity:

Do a continuity check AWM 715134 of the WO3 harness between:
.Pin P14/m of the EEC and pin P107/42 of 4101VC
.Pin P14/k of the EEC and pin P107/43 of 4101VC.

e If there is no continuity:

Replace the W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802.
Do the test given in Para. 3.

(4) If the fault continues:

Replace the [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
Do the test given in Para. 3.

5. Close-up
Subtask 30-21-00-942-064-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl-doors AMM 71-13-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:29:32 UTC