T3 Sensor Signal Disagreement

TASK 73-21-00-810-864-A
T3 Sensor Signal Disagreement

1. Possible Causes

PROBE-T3 [4084KS]
W04 HARNESS [4088KS]
W03 HARNESS [4087KS]
HARNESS-EGT/T3, WC05 [4207KS]
[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 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 73-21-24-000-801	Removal of the T3 Probe
AMM 73-21-24-400-801	Installation of the T3 Probe
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)
AMM 77-21-61-000-802	Removal of the Exhaust Gas Temperature (EGT) (T5/T3) Wiring Harness (WC05)
AMM 77-21-61-400-802	Installation of the Exhaust Gas Temperature (EGT) (T5/T3) Wiring Harness (WC05)
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
W03/W04 Harness Interconnect
W03/WC05 Interconnect Wiring Harness
T3 Probe Wiring Harness
T3 Probe Wiring Schematic

3. Fault Confirmation
Subtask 73-21-00-710-115-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 T3 probe do not agree between channel A and B. The T3 Probe is attached to the diffuser case, 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 73-21-00-810-136-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 W04 (4088KS), W03 (4087KS) and WC05 (4207KS) harnesses, connectors P13 (4000KS-P13) and P14 (4000KS-P14) - EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A), interconnec J43 (4109VC)/P43 (4109VC-A) and Kp/Kn lugs - T3 probe (4084KS), for problems which are possible between the EEC (4000KS) and the T3 probe (4084KS).
(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) Do a check of the nuts that connect the WC05 (4207KS) harness lugs to the T3 probe Kn and Kp studs for proper torque AMM 77-21-61-400-802.
(d) If a problem is found with the harness or connectors:
1 Replace W04 HARNESS(4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS(4087KS) AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
3 Replace HARNESS-EGT & T3, WC05(4207KS) AMM 77-21-61-000-802 and AMM 77-21-61-000-802.
4 Do the test given in Para. 3.
(3) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connectors P13 (4000KS-P13) and P14 (4000KS-P14) from the EEC (4000KS), interconnect J107 (4101VC)/P107(4101VC-A), interconnect J43 (4109VC)/ P43 (4109VC-A) and Kp/Kn lugs from the T3 probe (4084KS).
(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) Examine the WC05 (4207KS) harness lugs, T3 probe (4084KS) studs and removed nut for damage.
(c) 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.
(d) Reconnect the electrical connector P13 (4000KS-P13) and P14 (4000KS-P14) to the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A), interconnect J43 (4109VC)/P43 (4109VC-A) and Kp/Kn lugs to the T3 probe (4084KS).
(e) Make sure that the nuts that connect the WC05 (4207KS) harness lugs to the T3 probe Kn and Kp studs are properly torqued AMM 77-21-61-400-802.

NOTE: The nuts that connect the WC05 (4207KS) harness lugs to the T3 probe Kn and Kp studs have different torque values.

(f) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace PROBE-T3 [4084KS] AMM 73-21-24-000-801 and AMM 73-21-24-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P13 (4000KS-P13) and P14 (4000KS-P14) from the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A), interconnect J43 (4109VC)/ P43 (4109VC-A) and Kp/Kn lugs from the T3 probe (4084KS). Use a MULTIMETER - STANDARD to test the T3 probe (4084KS) channel A and channel B circuit in the harnesses. Refer to Table 1 and Table 2. 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: T3 Probe Channel A Connector Contacts

W04(4088KS) Harness P13 (4000KS-P13) EEC(4000KS) Connector Contacts	W04(4088KS) Harness J107 (4101VC) Connector Contacts	W03(4087KS) Harness P107 (4101VC-A) Connector Contacts	W03(4087KS) Harness J43 (4109VC) Connector Contacts	WC05(4207KS) Harness P43 (4109VC-A) Connector Contacts	WC05(4207KS) Harness Kp/ Kn T3 probe (4084KS) Connector Contacts
P	30	30	16	16	Kp
i	31	31	17	17	Kn

Table 2: T3 Probe Channel B Connector Contacts

W03 (4087KS) Harness P14 (4000KS-P14) EEC (4000KS) Connector Contacts	W03 (4087KS) Harness J43 (4109VC) Connector Contacts	WC05 (4207KS) Harness P43 (4109VC-A) Connector Contacts	WC05 (4207KS) Harness Kp/Kn T3 Probe (4084KS) Contacts
P	13	13	Kp
i	14	14	Kn

(b) If a problem is found with the harnesses or connectors:
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
3 Replace HARNESS-EGT/T3, WC05 [4207KS] AMM 77-21-61-000-802 and AMM 77-21-61-400-802.
4 Do the test given in Para. 3.
(6) If no problems are found with the harness or the fault continues:
(a) Replace [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 73-21-00-860-056-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 thrust reverser cowl-doors AMM 78-36-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:36:38 UTC