3. Fault Confirmation
__________________
 A. Do the operational test of the FADEC 1B on the ground (with engine non motoring) (Ref. AMM TASK 73-29-00-710-040).
 4. Fault Isolation
_______________

 A. If the test gives the maintenance message T495 SNSR, J13, ECU:
 - do a check for open or short to ground of the T495 thermocouple and of the harness HJ13 between the ECU (4000KS), the 6 o'clock junction box and the T495 thermocouple (Ref. AWM 71-51-05) and (Ref. ASM 73-25/15).
 (1) If the wiring is not correct:

 - repair the above wiring.

 (2) If the wiring is correct:

 - disconnect the harness HJ13 from the ECU (4000KS) and do a resistance check of the cable between: . pins 12 and 13 (1 to 10 ohms) . pins 12 and 24 (> 10 megohms) . pin 12 and the ground (> 10 megohms).
 (a) If the resistance values are in the specified limits:

 - replace the ECU (4000KS) (Ref. AMM TASK 73-21-60-000-001) and (Ref. AMM TASK 73-21-60-400-001).

 (b) If the resistance values are out of the specified limits:

 - disconnect the harness CJ13 at the 6 o'clock junction box and do a resistance check of the harness CJ13 between: . pins 3 and 13 (1 to 10 ohms) . pins 3 and 12 (> 10 megohms) . pin 3 and the ground (> 10 megohms).
 1 If the resistance values are in the specified limits:
_

 - replace the harness HJ13 (Ref. AMM TASK 73-21-50-000-046) and (Ref. AMM TASK 73-21-50-400-046).
 2 If the resistance values are out of the specified limits:
_

 - disconnect the harness CJ13 from the T495 thermocouple and do a resistance check of the T495 thermocouple between: . pins A and B (1 to 10 ohms) . pin A and the ground (> 10 megohms).
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 a If the resistance values are in the specified limits:

_

 - replace the harness CJ13 (Ref. AMM TASK 73-21-50-000-029) and (Ref. AMM TASK 73-21-50-400-029).
 b If the resistance values are out of the specified limits,
_ do an inspection/check of the T495 thermocouple wiring harness for isolation of the defective part (Ref. AMM TASK 77-21-10-200-002).
 - if the electrical check of one of the three two-probe lead assemblies is not correct, replace the defective thermocouple: . the lower left-hand thermocouple lead assembly (Ref. AMM TASK 77-21-10-000-027) and (Ref. AMM TASK 77-21-10-400-027) or . the lower right-hand thermocouple lead assembly (Ref. AMM TASK 77-21-10-000-029) and (Ref. AMM TASK 77-21-10-400-029) or . the upper left-hand thermocouple lead assembly (Ref. AMM TASK 77-21-10-000-028) and (Ref. AMM TASK 77-21-10-400-028).

 - if the electrical check of the three-probe lead assembly is not correct: . replace the three-probe thermocouple lead assembly (Ref. AMM TASK 77-21-10-000-026) and (Ref. AMM TASK 77-21-10-400-026), (Ref. AMM TASK 77-21-10-000-027) and (Ref. AMM TASK 77-21-10-400-027), (Ref. AMM TASK 77-21-10-000-028) and (Ref. AMM TASK 77-21-10-400-028), (Ref. AMM TASK 77-21-10-000-029) and (Ref. AMM TASK 77-21-10-400-029).

 - if the electrical check of the upper extension lead is not correct: . replace the upper extension lead (Ref. AMM TASK 77-21-10-000-008) and (Ref. AMM TASK 77-21-10-400-008).

 - if the electrical check of the lower extension lead is not correct: . replace the lower extension lead (Ref. AMM TASK 77-21-10-000-009) and (Ref. AMM TASK 77-21-10-400-009).

 - if the electrical check of the main junction box assembly is not correct: . replace the main junction box assembly (Ref. AMM TASK 77-21-10-000-025) and (Ref. AMM TASK 77-21-10-400-025).

 B. Do the test given in Para. 3.A. R
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 Loss of the EGT Thermocouple Signal to the ECU on Engine 2
 1. Possible Causes
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 - harness HJ13

 - ECU (4000KS)

 - harness CJ13

 - lower left-hand thermocouple lead assembly

 - lower right-hand thermocouple lead assembly

 - upper left-hand thermocouple lead assembly

 - three-probe thermocouple lead assembly

 - upper extension lead

 - lower extension lead

 - main junction box assembly

 2. Job Set-up Information
　
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