T3 CJC Sensor Signal Disagreement

TASK 73-21-00-810-895-A
T3 CJC Sensor Signal Disagreement

1. Possible Causes

W03 HARNESS [4087KS]
W04 HARNESS [4088KS]
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 73-21-63-000-802	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 Cold Junction Compensation Wiring Schematic

3. Fault Confirmation
Subtask 73-21-00-710-148-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) channel A and channel B have detected that the T3 probe cold junction compensation circuits do not agree. The T3 probe cold junction compensation circuit is integrated within the WC05 wiring harness connector P43 and has a resistance temperature device that provides a temperature reference to the EEC. The T3 probe is located on 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 harness 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 73-21-00-810-167-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 W03 (4087KS), W04 (4088KS) and WC05 (4207KS) harnesses, connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and interconnect J43 (4109VC)/P43 (4109VC-A), for problems which are possible between the EEC (4000KS) and the T3 probe (4084KS) cold junction compensation circuits.
(a) Inspect for harnesses 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 the W03 HARNESS(4087KS) AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace the W04 HARNESS(4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
3 Replace the WC05 HARNESS-EGT/T3(4207KS) AMM 77-21-61-000-802 and AMM 77-21-61-400-802.
4 Do the test given in Para. 3.
(3) If no problems are found with the harnesses or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and interconnect J43 (4109VC)/P43 (4109VC-A).
(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 connector face AMM 70-70-00-910-803.
(c) Reconnect the electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) to the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and interconnect J43 (4109VC)/P43 (4109VC-A).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Disconnect the electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and interconnect J43 (4109VC)/P43 (4109VC-A). Use a MULTIMETER - STANDARD to test the T3 probe (4084KS) cold junction compensation channel A and channel B circuits 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 Cold Junction Compensation Channel A Connector Contacts

W04 (4088KS) Harness P3 (4000KS-P3) 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
H	53	53	4	4
G	54	54	5	5

Table 2: T3 Probe Cold Junction Compensation Channel B Connector Contacts

W03 (4087KS) Harness P4 (4000KS-P4) EEC (4000KS) Connector Contacts	W03 (4088KS) Harness J43 (4109VC) Connector Contacts	WC05 (4207KS) Harness P43 (4109VC-A) Connector Contacts
H	7	7
G	8	8

(b) If a problem is found with the harnesses or connectors:
1 Replace the W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
3 Replace the 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.
(5) If no problems are found:
(a) Replace the HARNESS-EGT/T3, WC05 [4207KS] AMM 77-21-61-000-802 and AMM 77-21-61-400-802.
(b) Do the test given in Para. 3.
(6) If 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 73-21-00-860-087-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 04:36:42 UTC