Downstream NAI Pressure Transducer Signal Failure on Channel B

TASK 30-21-00-810-815-A
Downstream NAI Pressure Transducer Signal Failure on Channel B

1. Possible Causes

W04 HARNESS [4088KS]
PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 2 [4003DN]
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 30-21-23-000-801	Removal of the Nacelle Anti-Ice Fan-Pressure-Transducer
AMM 30-21-23-400-801	Installation of the Nacelle Anti-Ice Fan-Pressure-Transducer
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 30-21-00-730-052-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 Channel 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 30-21-00-810-064-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 P17 of the W04 harness is correctly engaged in the socket of the NAI core pressure-transducer.
(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 P17 from the receptacle of the NAI fan pressure-transducer:

Do a visual inspection of the electrical connector P17 and of the receptacle J17 of the NAI core pressure-transducer for bent pins,contamination or corrosion or visual signs of damage.

(a) If you find damage on electrical connector P17:

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 you find damage on the receptacle J17:

Replace the PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 2 [4003DN] AMM 30-21-23-000-801 and AMM 30-21-23-400-801.
Do the test given in Para. 3.

(c) If you find no damage on the receptacle J17 and on the electrical connector P17:
1 Do a resistance check AWM 715134 between:

Pin J17/9 and pin J17/8 of the NAI fan pressure-transducer
Pin J17/6 and pin J17/7 of the NAI fan pressure-transducer.

a If the resistance is more than 12.5 kohm:

Replace the PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 2 [4003DN] AMM 30-21-23-000-801 and AMM 30-21-23-400-801.
Do the test given in Para. 3.

b If the resistance is less than 12.5 kohm:

Use PLIERS - JAWED, SOFT to disconnect the electrical connector P106 of the 4100VC.
Do a visual inspection on the electrical connector P106 of the WO3 harness for bent pins, contamination, corrosion or visual signs of damage.

2 If you find damage on electrical connector P106:

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.

3 If there is no damage or if fault continues, do continuity check AWM 715134 of the WO3 harness between:
. Pin J106/11 of 4100VC and pin P17/9 of the NAI fan pressure-transducer
. Pin J106/12 of 4100VC and pin P17/8 of the NAI fan pressure-transducer
. Pin J106/25 of 4100VC and pin P17/7 of the NAI fan pressure-transducer
. Pin J106/26 of 4100VC and pin P17/6 of the NAI fan pressure-transducer.
a If there is no continuity:

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

4 If there is no damage or if fault continues, do a check AWM 715134 of the WO4 harness between:
. Pin P106/11 of 4100VC and pin P14/q of the EEC
. Pin P106/12 of 4100VC and pin P14/BB of the EEC
. Pin P106/25 of 4100VC and pin P14/p of the EEC
. Pin P106/26 of 4100VC and pin P14/T of the EEC.
a 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.

(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 30-21-00-942-056-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