EGT Sensor Electrical Failure Channel B

TASK 77-21-00-810-809-A
EGT Sensor Electrical Failure Channel B

1. Possible Causes

THERMOCOUPLE-EGT, UPPER R [4061KS]
THERMOCOUPLE-EGT, LOWER R [4063KS]
W03 HARNESS [4087KS]
HARNESS-EGT/T3, WC05 [4207KS]
OIL TEMPERATURE PROBE [4073KS]
[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 77-21-21-000-801	Removal of the Exhaust Gas Temperature (EGT) Probe
AMM 77-21-21-400-801	Installation of the Exhaust Gas Temperature (EGT) Probe
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
AMM 79-32-21-000-801	Removal of the Oil Temperature Probe
AMM 79-32-21-400-801	Installation of the Oil Temperature Probe
EEC Wiring Harnesses
Oil Temperature Probe Wiring Harness
EGT Wiring Schematic
EGT Channel B Wiring Harness

3. Fault Confirmation
Subtask 77-21-00-710-058-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 Exhaust Gas Temperature (EGT) probes is out of range or rate in channel B. There are four EGT probes mounted on the Turbine Exhaust Case (TEC). The EGT probes for the channel B circuit are located at the 2 and 4 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 77-21-00-810-060-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) and WC05 (4207KS) harnesses, connector P14 (4000KS-P14) - EEC (4000KS), connector P33 (4073KS-P33) - oil temperature probe (4073KS), interconnect J43 (4109VC)/P43 (4109VC-A) and Kp/Kn lugs - EGT probe (4061KS) and EGT probe (4063KS), for problems which are possible between the EEC (4000KS), EGT probe (4061KS) and EGT probe (4063KS).
(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 EGT probe (4061KS) and EGT probe (4063KS) Kn and Kp studs for proper torque AMM 77-21-61-400-802.
(d) If a problem is found with the harnesses or connectors:
1 Replace W03 HARNESS(4087KS) AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace W05 HARNESS(4207KS) AMM 77-21-61-000-802 and AMM 77-21-61-400-802.
3 Do the test given in Para. 3.
(3) If no problems are found with the harnesses, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P14 (4000KS-P14) from the EEC (4000KS), connector P33 (4073KS-P33) from the oil temperature probe (4073KS), interconnect J43 (4109VC)/P43 (4109VC-A) and Kp/Kn lugs from the EGT Probe (4061KS) and EGT Probe (4063KS).
(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, EGT probe (4061KS) and EGT probe (4063KS) studs, and removed nuts 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 P14 (4000KS-P14) to the EEC (4000KS), connector P33 (4073KS-P33) to the oil temperature probe (4073KS), interconnect J43 (4109VC)/P43 (4109VC-A) and Kp/Kn lugs to the EGT probe (4061KS) and EGT probe (4063KS).
(e) Make sure that the nuts connect the WC05 (4207KS) harness lugs to the EGT probe (4061KS) and EGT probe (4063KS) 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 EGT probe (4061KS) and EGT probe (4063KS) Kn and Kp studs have different torque values.

(f) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace THERMOCOUPLE-EGT, UPPER R [4061KS] AMM 77-21-21-000-801 and AMM 77-21-21-400-801 at the 2 o'clock position, and
(b) Replace THERMOCOUPLE-EGT, LOWER R [4063KS] AMM 77-21-21-000-801 and AMM 77-21-21-400-801 at the 4 o'clock position.
(c) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P14 (4000KS-P14) from the EEC (4000KS), connector P33 (4073KS-P33) from the oil temperature probe (4073KS), interconnect J43 (4109VC)/P43 (4109VC-A) and Kp/Kn lugs from the EGT probe (4061KS) and EGT probe (4063KS). Use a MULTIMETER - STANDARD to test the EGT probe (4061KS) and EGT probe (4063KS) 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: EGT harness wires from the oil temperature probe to the EGT probes are chromel and alumel. These wires may have higher resistance during continuity checks. Typically less than 20 ohms is acceptable.

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

Table 1: EGT Channel B Circuit, EEC to EGT Probes Connector Contacts

W03 (4087KS) Harness P14 (4000KS-P14) EEC(4000KS) Connector Contacts	W03 (4087KS) Harness P33 (4073KS-P33) Oil Temperature Probe (4073KS) Connector Contacts	W03 (4087KS) Harness P33 (4073KS-P33) Oil Temperature Probe (4073KS) Connector Contacts	W03 (4087KS) Harness J43 (4109VC) Connector Contacts	WC05(4207KS) Harness P43 (4109VC-A) Connector Contacts	WC05(4207KS) Harness Kp/Kn EGT Probe (4061KS) and EGT Probe (4063KS) Contacts
n	8	7	23	23	Kp
R	10	9	24	24	Kn

(b) If a problem is found with the harnesses or connectors:
1 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace HARNESS-EGT/T3, WC05 [4207KS] AMM 77-21-21-000-801 and AMM 77-21-21-400-801.
3 Do the test given in Para. 3.
(6) If no problems are found with the harnesses or the fault continues:
(a) Replace OIL TEMPERATURE PROBE [4073KS] AMM 79-32-21-000-801 and AMM 79-32-21-400-801.
(b) Do the test given in Para. 3.
(7) 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 77-21-00-860-051-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 04:37:56 UTC