T2 Engine Sensor Signal Failure Channel B

TASK 73-21-00-810-872-A
T2 Engine Sensor Signal Failure Channel B

1. Possible Causes

T2 PROBE [4001KS]
HARNESS-FAN, WF01 [4217KS]
HARNESS-FAN, WF02 [4218KS]
HARNESS-T2 PROBE [4110KS]
[4000KS]

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

REFERENCE	QTY	DESIGNATION
No specific	1	MULTIMETER - STANDARD
No specific	1	PLIERS - JAWED, SOFT

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 71-00-00-810-834-A	General Troubleshooting Guidelines for Additional Troubleshooting Information
TSM TASK 71-00-00-810-835-A	Component and Harness Intermittent Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults
AMM 70-70-00-910-803	SPOP 6 - Cleaning of the Contact Points and Wiring Harnesses
AMM 71-61-12-000-801	Removal of the T2 Probe
AMM 71-61-12-400-801	Installation of the T2 Probe
AMM 71-61-51-000-801	Removal of the Inlet Cowl T2-Probe Harness
AMM 71-61-51-400-801	Installation of the Inlet Cowl T2-Probe Harness
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 73-21-61-000-802	Removal of the Electronic Engine Control (EEC) Wiring Harness (WF01)
AMM 73-21-61-400-802	Installation of the Electronic Engine Control (EEC) Wiring Harness (WF01)
AMM 73-21-62-000-802	Removal of the EEC Wiring Harness (WF02)
AMM 73-21-62-400-802	Installation of the EEC Wiring Harness (WF02)
AMM 78-36-00-010-802	Opening of the Thrust Reverser Cowl-Doors
AMM 78-36-00-410-802	Closing of the Thrust Reverser Cowl-Doors
EEC Wiring Harnesses
T2 Probe Wiring Harness
T2 Probe Wiring Schematic
WF02/WN30 Interconnect Wiring Harness

3. Fault Confirmation
Subtask 73-21-00-710-123-A ** ON A/C NOT FOR ALL

A. Do the EEC system interactive test to confirm this fault. Refer to FADEC self test AMM 73-21-00-710-806.

NOTE: The Electronic Engine Control (EEC) has detected the circuit for the T2 probe is out of range or rate in channel B. The T2 probe is mounted on the fan cowling, located at the 1 o'clock position.

Refer to the general troubleshooting guidelines for additional troubleshooting information (Ref. TSM TASK 71-00-00-810-834).
Refer to the component and harness intermittent troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).

(1) If the maintenance message does not come back, examine the harnesses and electrical connectors as described in the component and harness intermittent fault isolation procedure (Ref. TSM TASK 71-00-00-810-835).
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(2) If the maintenance message comes back (hard fault), 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.

WARNING: REFER TO THE MSDS FOR ALL MATERIAL USED AND THE MANUFACTURER'S SAFETY INSTRUCTIONS FOR ALL EQUIPMENT USED. 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 73-21-00-810-144-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Examine the WF01 (4217KS), WF02 (4218KS) and WN30 (4110KS) harnesses and connector P2 (4000KS-P2) - EEC (4000KS), interconnect P103 (4105VC-A)/J103 (4105VC) and interconnect P122 (4106VC-A)/J122 (4106VC) and connector P22 (4001KS-P22) - T2 probe (4001KS), for problems which are possible between the EEC (4000KS) and the T2 probe (4001KS).
(a) Inspect for harness damage.
(b) Inspect for loose or damaged connectors.

NOTE: Loose connectors must be disconnected and examined for further wear or damage.

(c) If a problem is found with the harnesses or connectors:
1 Replace HARNESS-FAN, WF01(4217KS) AMM 73-21-61-000-802 and AMM 73-21-61-400-802, or
2 Replace HARNESS-FAN, WF02(4218KS) AMM 73-21-62-000-802 and AMM 73-21-62-400-802, or
3 Replace HARNESS-T2 PROBE(4110KS) AMM 71-61-51-000-801 and AMM 71-61-51-400-801.
4 Do the test given in Para. 3.
(3) If no problems are found with the harnesses, use a PLIERS - JAWED, SOFT to disconnect electrical connector P2 (4000KS-P2) from the EEC (4000KS), interconnect P103 (4105VC-A)/J103 (4105VC) and interconnect P122 (4106VC-A)/J122 (4106VC) and connector P22 (4001KS-P22) from the T2 probe (4001KS).
(a) Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face. Replace parts as necessary.
(b) Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across the connector face AMM 70-70-00-910-803.
(c) Reconnect electrical connector P2 (4000KS-P2) to the EEC (4000KS), interconnect P103 (4105VC-A)/J103 (4105VC) and interconnect P122 (4106VC-A)/J122 (4106VC) and connector P22 (4001KS-P22) to the T2 probe (4001KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace T2 PROBE [4001KS] AMM 71-61-12-000-801 and AMM 71-61-12-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect electrical connector P2 (4000KS-P2) from the EEC (4000KS), interconnect P103 (4105VC-A)/J103 (4105VC) and interconnect P122 (4106VC-A)/J122 (4106VC) and connector P22 (4001KS-P22) from the T2 probe (4001KS). Use a MULTIMETER - STANDARD to test the T2 probe (4001KS) channel B circuit in the harnesses. Refer to Table 1. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).

NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.

Table 1: T2 Probe Channel B Connector Contacts

WF01 (4217KS) Harness P2 (4000KS-P2) EEC (4000KS)	WF01 (4217KS) Harness P103 (4105VC-A)	WF02 (4218KS) Harness J103 (4105VC)	WF02 (4218KS) Harness P122 (4106VC-A)	WN30 (4110KS) Harness J122 (4106VC)	WN30 (4110KS) Harness P22 (4001KS-P22) T2 Probe (4001KS)
P	1	1	9	9	9
R	2	2	10	10	10
n	3	3	2	2	2

(b) If a problem is found with the harnesses or connectors:
1 Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802, or
2 Replace HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802, or
3 Replace HARNESS-T2 PROBE [4110KS] AMM 71-61-51-000-801 and AMM 71-61-51-400-801.
4 Do the test given in Para. 3.
(6) If the fault continues:
(a) Replace the [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
(b) Do the test given in Para. 3.

5. Close-up
Subtask 73-21-00-860-064-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 thrust reverser cowl-doors AMM 78-36-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:36:39 UTC