Failure of the Thrust Reverser Inhibition Switch - Engine 1 - Channel A

TASK 71-50-00-810-805-A
Failure of the Thrust Reverser Inhibition Switch - Engine 1 - Channel A

1. Possible Causes

EIU-1 [1KS1]
SEC-1 [1CE1]
SEC-2 [1CE2]
RELAY-THRUST REV INHIBITION, ENG 1 [14KS1]
thrust reverser harness
aircraft wiring
ECU [4000KS]
CTL UNIT-THROTTLE, ENG 1 [8KS1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 27-94-34-000-001	Removal of the SEC
AMM 27-94-34-400-001	Installation of the SEC
AMM 71-51-43-000-044	Removal of the Thrust Reverser (Channel A and B) Harness
AMM 71-51-43-400-044	Installation of the Thrust Reverser (Channel A and B) Harness
AMM 71-51-44-000-002	Removal of the Thrust Reverser Harness 238W0908
AMM 71-51-44-400-002	Installation of the Thrust Reverser Harness 238W0908
AMM 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
ASM 732516
AMM 73-25-34-000-040	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-040	Installation of the Engine Interface Unit (EIU)
AMM 76-11-19-000-040	Removal of the Throttle Control Unit
AMM 76-11-19-000-042	Removal of the Throttle Control Unit
AMM 76-11-19-400-040	Installation of the Throttle Control Unit
AMM 76-11-19-400-042	Installation of the Throttle Control Unit
AMM 78-31-00-710-040	Operational Test of the Thrust Reverser System
AMM 78-31-00-710-042	Operational Test of the Thrust Reverser System
ASM 783701

3. Fault Confirmation
Subtask 71-50-00-860-050-A ** ON A/C NOT FOR ALL

A. Make sure that the throttle lever is not in the thrust reverser area.

Subtask 71-50-00-710-058-A ** ON A/C NOT FOR ALL

B. Do the operational test of the thrust reverser system AMM 78-31-00-710-040.

Subtask 71-50-00-710-058-B ** ON A/C NOT FOR ALL

B. Do the operational test of the thrust reverser system AMM 78-31-00-710-042.

4. Fault Isolation
Subtask 71-50-00-810-058-A ** ON A/C NOT FOR ALL

A. This fault message is generated when the ECU detects an unwanted closure of the inhibition relay 14KS1 or a short or short to ground in the harness J5 or in the thrust reverser harness or in the aircraft wiring.

CAUTION: MAKE SURE THAT THERE IS NO HYDRAULIC PRESSURE WHILE YOU DO THIS TEST. PUT A WARNING NOTICE IN THE COCKPIT TO TELL PERSONS NOT TO PRESSURIZE THE HYDRAULIC SYSTEMS.

(1) If the test gives the maintenance message J5, TR INHIBIT SW:

on the overhead panel 50VU, push and release the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend comes on,
remove the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) from 187VU and do a check for 28VDC at pin A/X on the relay base ASM 732516.

(a) If there is 28VDC:

on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
remove the EIU1 (1KS1) AMM 73-25-34-000-040, the SEC1 (1CE1) and the SEC2 (1CE2) AMM 27-94-34-000-001,
do a check for a short to ground between ASM 732516,
.the EIU1 (1KS1) pin AA/4C and the SEC1 (1CE1) pin AB/15E
.the EIU1 (1KS1) pin AA/4A and the SEC2 (1CE2) pin AB/15E.

1 If there is a short to ground:

repair as required.

2 If nothing is found:

replace the EIU-1 [1KS1] AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

3 If the fault continues:

replace the SEC-1 [1CE1] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

4 If the fault continues:

replace the SEC-2 [1CE2] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

(b) If there is no 28VDC:

on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
replace the RELAY-THRUST REV INHIBITION, ENG 1 [14KS1] on 187VU ASM 732516.

1 If the fault continues:

disconnect the harness J5 from the ECU (4000KS),
do a resistance check between:
. pins 7 and 8 (>10 megohms)
. pins 7 and 11 (>10 megohms)
. pin 7 and the ground (>10 megohms).

a If there is an electrical short or a short to ground:

replace the thrust reverser harness AMM 71-51-44-000-002 and AMM 71-51-44-400-002 or repair the aircraft wiring to the relay 14KS1 ASM 732516.

2 If nothing is found:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

(2) If the test does not give the maintenance message J5, TR INHIBIT SW:

replace the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) on 187VU ASM 732516.

(a) If the fault continues:

replace the EIU-1 (1KS1) AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

(b) If the fault continues:

replace the SEC-1 (1CE1) AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

replace the SEC-2 (1CE2) AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

(d) If the fault continues:

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

(e) If the fault continues:

do a check for a short to ground between ASM 732516:
.the EIU1 (1KS1) pin AA/4C and the SEC1 (1CE1) pin AB/15E
.the EIU1 (1KS1) pin AA/4A and the SEC2 (1CE2) pin AB/15E
.the relay (14KS1) and its related wiring.

1 If nothing is found:

replace the thrust reverser harness AMM 71-51-44-000-002 and AMM 71-51-44-400-002.

Subtask 71-50-00-810-058-D ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THERE IS NO HYDRAULIC PRESSURE WHILE YOU DO THIS TEST. PUT A WARNING NOTICE IN THE COCKPIT TO TELL PERSONS NOT TO PRESSURIZE THE HYDRAULIC SYSTEMS.

(1) Do a check of the Post Flight Report (PFR) or of the FADEC Scheduled Maintenance Report (SMR).

NOTE: With ECU PN 1459M55P28, 1519M83P15, 1820M27P12 or with all previous part numbers, any of the following failures may unduly trigger the ECAM warning ENG X REV SWITCH FAULT at ECU power-up:
ECU (CPU)
ECU (15 VDC FAULT)
ECU (25 VDC FAULT)
ECU (CCDL)
ECU(NVM FAULT)
ECU(ARINC OUT)
ALT, J10, ECU
J7 or J8, HMU(FMV TM), ECU
J7 or J8, HMU(VSV TM), ECU
J7 or J8, HMU(VBV TM), ECU
J7 or J8, HMU(HPTCTM), ECU
J7 or J8, HMU(LPTCTM), ECU
J7 or J8, HMU(BSVSOL), ECU
J7 or J8, FRV, ECU
SAV (SOL), J9 or J10, ECU
*HCU(TRPV), J5 or J6, ECU
*STOW SW, J5 or J6, ECU
DPLSTW SW, 5/6, ECU
HCU(TRDV), J5 or J6, ECU
The ECU PN may be checked by getting access to the FADEC LRU identification screen on the MCDU.

(a) If any of the above failure messages is found in the Post Flight Report (PFR) or in the FADEC Scheduled Maintenance Report (SMR):

clear this (these) fault(s) first.

(b) If none of the above failure messages was found:

do the normal trouble shooting procedure described below.

(2) If the test gives the maintenance message J5, TR ACFT SW, ECU:

on the overhead panel 50VU, push and release the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend comes on,
remove the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) from 187VU and do a check for 28VDC at pin A/X on the relay base ASM 732516.

(a) If there is 28VDC:

disconnect the connector E from the TCU1 (8KS1) and do a check for ground at pin E/C.

1 If there is ground:

replace the CTL UNIT-THROTTLE, ENG 1 [8KS1] AMM 76-11-19-000-040 and AMM 76-11-19-400-040.

2 If there is no ground:

on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
remove the EIU1 (1KS1) AMM 73-25-34-000-040 and disconnect the connector E from the TCU1 (8KS1),
do a check for a short to ground between ASM 783701:
.the EIU1 (1KS1) pin AA/4C and the TCU1 (8KS1) pin E/C
.the EIU1 (1KS1) pin AA/4A and the TCU1 (8KS1) pin E/C.

3 If there is a short to ground:

repair as required.

4 If nothing is found:

replace the EIU-1 [1KS1] AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

(b) If there is no 28VDC:

on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
replace the RELAY-THRUST REV INHIBITION, ENG 1 [14KS1] on 187VU ASM 732516.

1 If the fault continues:

disconnect the harness J5 from the ECU (4000KS),
do a resistance check between:
. pins 7 and 8 (>10 megohms)
. pins 7 and 11 (>10 megohms)
. pin 7 and the ground (>10 megohms).

a If there is an electrical short or a short to ground:

replace the thrust reverser harness AMM 71-51-44-000-002 and AMM 71-51-44-400-002 or repair the aircraft wiring to the relay 14KS1 ASM 732516.

2 If nothing is found:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

(3) If the test does not give the maintenance message J5, TR ACFT SW, ECU:

replace the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) on 187VU ASM 732516.

(a) If the fault continues:

replace the EIU-1 (1KS1) AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

(b) If the fault continues:

replace the CTL UNIT-THROTTLE, ENG 1 (8KS1) AMM 76-11-19-000-040 and AMM 76-11-19-400-040.

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

(d) If the fault continues:

do a check for a short to ground between ASM 732516:
.the EIU1 (1KS1) pin AA/4C and the TCU1 (8KS1) pin E/C
.the EIU1 (1KS1) pin AA/4A and the TCU1 (8KS1) pin E/C
.the relay (14KS1) and its related wiring.

1 If nothing is found:

replace the thrust reverser harness AMM 71-51-44-000-002 and AMM 71-51-44-400-002.

Subtask 71-50-00-810-058-F ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THERE IS NO HYDRAULIC PRESSURE WHILE YOU DO THIS TEST. PUT A WARNING NOTICE IN THE COCKPIT TO TELL PERSONS NOT TO PRESSURIZE THE HYDRAULIC SYSTEMS.

(1) If the test gives the maintenance message J5, TR ACFT SW, ECU:

on the overhead panel 50VU, push and release the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend comes on,
remove the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) from 187VU and do a check for 28VDC at pin A/X on the relay base ASM 732516.

(a) If there is 28VDC:

disconnect the connector E from the TCU1 (8KS1) and do a check for ground at pin E/C.

1 If there is ground:

replace the CTL UNIT-THROTTLE, ENG 1 [8KS1] AMM 76-11-19-000-042 and AMM 76-11-19-400-042.

2 If there is no ground:

on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
remove the EIU1 (1KS1) AMM 73-25-34-000-040 and disconnect the connector E from the TCU1 (8KS1),
do a check for a short to ground between ASM 783701:
.the EIU1 (1KS1) pin AA/4C and the TCU1 (8KS1) pin E/C
.the EIU1 (1KS1) pin AA/4A and the TCU1 (8KS1) pin E/C.

3 If there is a short to ground:

repair as required.

4 If nothing is found:

replace the EIU-1 [1KS1] AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

(b) If there is no 28VDC:

on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
replace the RELAY-THRUST REV INHIBITION, ENG 1 [14KS1] on 187VU ASM 732516.

1 If the fault continues:

disconnect the harness J5 from the ECU (4000KS),
do a resistance check between:
. pins 7 and 8 (>10 megohms)
. pins 7 and 11 (>10 megohms)
. pin 7 and the ground (>10 megohms).

a If there is an electrical short or a short to ground:

replace the thrust reverser harness AMM 71-51-43-000-044 and AMM 71-51-43-400-044 or repair the aircraft wiring to the relay 14KS1 ASM 732516.

2 If nothing is found:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

(2) If the test does not give the maintenance message J5, TR ACFT SW, ECU:

replace the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) on 187VU ASM 732516.

(a) If the fault continues:

replace the EIU-1 (1KS1) AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

(b) If the fault continues:

replace the CTL UNIT-THROTTLE, ENG 1 (8KS1) AMM 76-11-19-000-042 and AMM 76-11-19-400-042.

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

(d) If the fault continues:

do a check for a short to ground between ASM 732516:
.the EIU1 (1KS1) pin AA/4C and the TCU1 (8KS1) pin E/C
.the EIU1 (1KS1) pin AA/4A and the TCU1 (8KS1) pin E/C
.the relay (14KS1) and its related wiring.

1 If nothing is found:

replace the thrust reverser harness AMM 71-51-43-000-044 and AMM 71-51-43-400-044.

Subtask 71-50-00-710-059-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.
(1) No additional maintenance action is required if the fault is not confirmed.
(2) Repeat the fault isolation procedure if the fault continues.

[Rev.8 from Aug 2018] 2026.04.04 04:34:57 UTC