T25 Engine Sensor Signal Failure Channel A

TASK 73-21-00-810-874-A
T25 Engine Sensor Signal Failure Channel A

1. Possible Causes

P2.5, T2.5 PROBE [4083KS]
W04 HARNESS [4088KS]
[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 73-21-22-000-801	Removal of the P2.5/T2.5 Probe
AMM 73-21-22-400-801	Installation of the P2.5/T2.5 Probe
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 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
P2.5/T2.5 Probe Wiring Harness
P2.5/T2.5 Probe Wiring Schematic

3. Fault Confirmation
Subtask 73-21-00-710-125-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 temperature circuit for the P2.5/T2.5 probe is out of range or rate in channel A. The P2.5/T2.5 probe is on the compressor intermediate 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 73-21-00-810-146-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) harness and connector P13 (4000KS-P13) - EEC (4000KS) and connector P45 (4083KS-P45) - P2.5/T2.5 probe (4083KS), for problems which are possible between the EEC (4000KS) and the P2.5/T2.5 probe (4083KS).
(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 harness or connectors:
1 Replace HARNESS-FAN, W04(4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 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 electrical connector P13 (4000KS-P13) from the EEC (4000KS), and connector P45 (4083KS-P45) from the P2.5/T2.5 probe (4083KS).
(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 P13 (4000KS-P13) to the EEC (4000KS) and connector P45 (4083KS-P45) to the P2.5/T2.5 probe (4083KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace P2.5, T2.5 PROBE [4083KS] AMM 73-21-22-000-801 and AMM 73-21-22-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect electrical connector P13 (4000KS-P13) from the EEC (4000KS) and connector P45 (4083KS-P45) from the P2.5/T2.5 probe (4083KS). Use a MULTIMETER - STANDARD to test the P2.5/T2.5 probe (4083KS) temperature circuit in the harness. 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: P2.5/T2.5 Probe Channel A Temperature Circuit Connector Contacts

W04 (4088KS) Harness P13 (4000KS-P13) EEC (4000KS) Connector Contacts	W04 (4088KS) Harness P45 (4083KS-P45) P2.5/T2.5 Probe (4083KS) Connector Contacts
F	5
KK	6

(b) 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.
2 Do the test given in Para. 3.
(6) If no problems are found with the harness or 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 73-21-00-860-066-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