DOC AIRBUS | TSM A320FLoss of the Fuel Metering Unit Control on Engine 1
1. Possible Causes
NOTE: This task is to troubleshoot the clear language message FMU/HC/EEC1. The fault acronyms listed in the
fault confirmation section below will help you focus on the correct cause of this clear language message.
· FMU ( 4000KC )
· EEC ( 4000KS )
· harness from the EEC connector (4000KS-J8) to the FMU (4000KC)
· harness from the EEC connector (4000KS-J2) to the FMU (4000KC)
· harness from the engine master control to the FMU (4000KC)
· harness from the EEC connector (4000KS-J2) to the FMU (4000KC)
· harness from the EEC connector (4000KS-J3) to the FMU (4000KC)
· CTL SW-ENG/MASTER 1 ( 3KC )
· harness from the EEC connector (4000KS-J8) to the FMU (4000KC)
· harness from the EEC connector (4000KS-J9) to the FMU (4000KC)
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
Ref. ESPM 20-45-21
Ref. AMM 24-41-00-861-002 Energize the Aircraft Electrical Circuits from the External Power
Ref. AMM 24-41-00-862-002 De-energize the Aircraft Electrical Circuits Supplied from the External
Power
Ref. AMM 31-10-00-700-001 Test Program after Removal/Installation of a VU panel
Ref. AMM 31-60-00-860-002 EIS Stop Procedure
Ref. AMM 70-23-15-912-010 Connection of Electrical Connectors
Ref. AMM 71-00-00-710-018 Discontinued Start, Restart and Shutdown Procedures
Ref. AMM 71-00-00-710-043 Normal Engine Automatic Start Procedure
Ref. AMM 71-00-00-710-047 Normal Engine Manual Start Procedure
Ref. AMM 71-13-00-410-010 Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
Ref. AMM 71-50-00-210-010 Wire Harness Visual Inspection - All Power Plant Electrical Cables
Ref. AMM 73-22-00-710-040 Operational Test of the FADEC SYSTEM on the Ground
Ref. AMM 73-22-34-000-010 Removal of the Electronic Engine Control (EEC)
Ref. AMM 73-22-34-400-010 Installation of the Electronic Engine Control (EEC)
REFERENCE DESIGNATION
Ref. AMM 73-22-52-000-010 Removal of the Fuel Metering Unit (FMU)
Ref. AMM 73-22-52-400-010 Installation of the Fuel Metering Unit (FMU)
Ref. ASM 73-25-18
Ref. ASM 76-12-01
Ref. AMM 78-30-00-440-012 Re-activation of the Thrust Reverser Hydraulic Control Unit (HCU) after
Ground Maintenance
Ref. AMM 78-32-00-410-010 Closing of the Thrust Reverser Halves
70-00-00-03-13 STANDARD PRACTICES - ENGINE - GENERAL - TASK SUPPORTING
DATA
Fuel Metering Unit SHEET 1
Fuel Shut-Off Valve SHEET 1
Figure 73(IAE)-22-00-991-01000-B / SHEET 1/1 - Fuel Metering Unit not printed, as per printing
preferences
Figure 73(IAE)-22-00-991-02400-B / SHEET 1/1 - Fuel Shut-Off Valve not printed, as per printing
preferences
3. Fault Confirmation
Subtask 73-22-00-860-198-A
A. Job Set-Up
(1) Energize the aircraft electrical circuits
Ref. AMM 24-41-00-861-002 .
(2) On the ENG section of the maintenance panel 50VU, put the FADEC GND PWR 1 pushbutton switch
to the ON position.
Subtask 73-22-00-710-234-A
B. Identification of Test to Make Sure that the Fault is Present
NOTE: Troubleshooting can start immediately without doing the fault confirmation if the clear language
message was indicated in multiple flights or ground legs.
(1) Do the CFDS message decoding to identify the fault acronym related to the clear language message
(Ref. TSM 70-00-00-03) .
(2) If the readout gives the fault acronym WONXCF or the fault acronym WFXCF in FADEC
1A or FADEC 1B, do the FADEC system operational test for fault confirmation Ref.
AMM 73-22-00-710-040 .
(a) If the test gives the fault acronym WONXCF in FADEC 1A or FADEC 1B, or there are two or
more occurrences in the fault history, continue with fault isolation Para. 4.A.
(b) If the test gives the fault acronym WFXCF in FADEC 1A or FADEC 1B, or there are two or more
occurrences in the fault history, continue with fault isolation Para. 4.B.
(c) If the test does not give the fault acronym WONFXCF or the fault acronym WFXCF, and there is
no history of faults, return the engine to the service.
(3) If the readout gives the fault acronym OSPXCF or the fault acronym OSFFMU in FADEC 1A or
FADEC 1B, do the steps in Para. 3.C. for fault confirmation.
(a) If the test gives the fault acronym OSPXCF, or there are two or more occurrences in the fault
history, continue with fault isolation Para. 4.C.
(b) If the test gives the fault acronym OSFFMU, or there are two or more occurrences in the fault
history, continue with fault isolation Para. 4.D.
(c) If the test does not give the fault acronym OSPXCF or fault acronym OSFFMU, and there is no
history of faults, return the engine to the service.
(4) If the readout gives the fault acronym WOFWAF or WONWAF in FADEC 1A or FADEC 1B, do the
FADEC system operational test for fault confirmation Ref. AMM 73-22-00-710-040 .
(a) If the test gives the fault acronym WOFWAF in FADEC 1A or FADEC 1B, or there are two or
more occurrences in the fault history, continue with fault isolation Para. 4.E.
(b) If the test gives the fault acronym WONWAF in FADEC 1A or FADEC 1B, or there are two or
more occurrences in the fault history, continue with fault isolation Para. 4.E.
Subtask 73-22-00-710-256-A
C. Test for Fault Acronym OSPXCF or Fault Acronym OSFFMU
(1) On the ENG section of the maintenance panel 50VU, put the FADEC GND PWR 1 pushbutton switch
to the ON position.
NOTE: This action resets the FADEC memory.
(2) Push the INIT mode key. The INIT page comes into view.
(3) Start engine 1 by doing the normal engine automatic start procedure Ref. AMM 71-00-00-710-043 or
the normal engine manual start procedure Ref. AMM 71-00-00-710-047 .
NOTE: You must operate the engine for a minimum of three minutes. If not, the LAST LEG REPORT
will not be erased and the fault will not be kept again in the EEC LAST LEG REPORT.
(4) Do the shutdown of engine 1 by doing the discontinued start, restart and shutdown procedures Ref.
AMM 71-00-00-710-018 .
(5) Read the LAST LEG REPORT and the scheduled maintenance report of the FADEC 1A and FADEC
1B menu on the MCDU (Ref. TSM 70-00-00-03) .
(a) Make a record of the fault message.
(b) Make a record of the channel, FADEC 1A or FADEC 1B, which found the fault.
(c) Do the CFDS message decoding and read the flight data and ground data to identify the fault
acronym.
4. Fault Isolation
(Ref. Fig. Fuel Metering Unit SHEET 1)
Subtask 73-22-00-810-097-A
A. Fault Isolation for Fault Acronym WONXCF
The shut-off valve switch signal does not agree with the signal from the opposite channel. This crosscheck
fault (XCF) is caused by an open, short-to-ground, or a wire-to-wire short in this circuit. This fault will
always be set in both channels.
NOTE: At any time during this procedure, you can do the steps in Para. 3 to make sure that the fault is
corrected.
NOTE: The removal and installation of the electrical connectors can correct this fault.
(1) If the fault was found in channel A, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J2) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace it as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-B) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel A shut-off valve switch circuit FMU in the (4000KC) Ref.
ASM 73-25-18:
1 Make sure that contacts N and M are not shorted to ground.
2 Make sure that contacts N and M are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact N to contact M is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect the electrical connector (4000KS-J2) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel A harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
FMU Shut-off Valve Switch Circuit Channel A Harness
FMU (4000KC) EEC (4000KS)
4000KC-B 4000KS-J2
Contacts Contacts
N B
M C
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WONXCF, return the engine to the service.
2 If the test gives the fault acronym WONXCF, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
(2) If the fault was found in channel B, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J8) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) If no problems were found with the harness, disconnect the electrical connector (4000KC-C) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel B shut-off valve switch circuit in the FMU (4000KC) Ref.
ASM 73-25-18:
1 Make sure that contacts N and M are not shorted to ground.
2 Make sure that contacts N and M are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact N to contact M is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect the electrical connector (4000KS-J8) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel B harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct position in each connector as specified
in the wiring diagram.
FMU Shut-off Valve Switch Circuit Channel B Harness
FMU (4000KC) EEC (4000KS)
4000KC-C 4000KS-J8
Contacts Contacts
N B
M C
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WONXCF, return the engine to the service.
2 If the test gives the fault acronym WONXCF, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
Subtask 73-22-00-810-192-A
B. Fault Isolation for Fault Acronym WFXCF
The resolver position signal does not agree with the signal from the opposite channel. This crosscheck
fault (XCF) is caused by an open, short-to-ground, or a wire-to-wire short in this circuit. This fault will
always be set in both channels.
NOTE: At any time during this procedure, you can do the steps in Para. 3 to make sure that the fault is
corrected.
NOTE: Removal and installation of the electrical connectors can correct this fault.
(1) If the fault was found in channel A, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J2) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace it as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-B) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel A resolver circuit in the FMU (4000KC) Ref. ASM
73-25-18:
1 Make sure that contacts E, C, D, B and A are not shorted to ground.
2 Make sure that contacts E, C, D, B and A are not shorted to any other contacts in the
connector.
3 Make sure that the resistance from contact E to contact D is between 15 and 78 ohms.
4 Make sure that the resistance from contact C to contact D is between 15 and 78 ohms.
5 Make sure that the resistance from contact B to contact A is between 54 and 103 ohms.
6 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect electrical connector (4000KS-J2) from the EEC (4000KS)
Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the resolver wiring in the channel A harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
FMU Resolver Circuit Channel A Harness
FMU (4000KC) EEC (4000KS)
(4000KC-B) (4000KS-J2)
Contacts Contacts
E W
C i
D j
B W
A A
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WFXCF, return the engine to the service.
2 If the test gives the fault acronym WFXCF, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
(2) If the fault was found in channel B, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J8) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 :
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) If no problems were found with the harness, disconnect the electrical connector (4000KC-C) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel B resolver circuit in the FMU (4000KC) Ref. ASM
73-25-18:
1 Make sure that contacts E, C, D, B and A are not shorted to ground.
2 Make sure that contacts E, C, D, B and A are not shorted to any other contacts in the
connector.
3 Make sure that the resistance from contact E to contact D is between 15 and 78 ohms.
4 Make sure that the resistance from contact C to contact D is between 15 and 78 ohms.
5 Make sure that the resistance from contact B to contact A is between 54 and 103 ohms.
6 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect the electrical connector (4000KS-J8) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel B harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
FMU Resolver Circuit Channel B Harness
FMU (4000KC) EEC (4000KS)
(4000KC-C) (4000KS-J8)
Contacts Contacts
E V
C i
D j
B W
A A
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WFXCF, return the engine to the service.
2 If the test gives the fault acronym WFXCF, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
Subtask 73-22-00-810-193-A
C. Fault Isolation for Fault Acronym OSPXCF
The overspeed valve position signal does not agree with the signal from the opposite channel. This
crosscheck fault (XCF) is caused by an open, short-to-ground, or a wire-to-wire short in this circuit. This
fault will always be set in both channels.
NOTE: At any time during this procedure, you can do the steps in Para. 3 to make sure that the fault is
corrected.
NOTE: The removal and installation of the electrical connectors can correct this fault.
(1) If the fault was found in channel A, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J2) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace it as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-B) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel A overspeed valve switch circuit in the FMU (4000KC)
Ref. ASM 73-25-18:
1 Make sure that contacts L and K are not shorted to ground.
2 Make sure that contacts L and K are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact L to contact K is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect electrical connector (4000KS-J2) from the EEC (4000KS)
Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel A harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
Overspeed Valve Switch Circuit Channel A Harness
FMU (4000KC) EEC (4000KS)
(4000KC-B) (4000KS-J2)
Contacts Contacts
L Y
K Z
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym OSPXCF, return the engine to the service.
2 If the test gives the fault acronym OSPXCF, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
(2) If the fault was found in channel B, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J8) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-C) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel B overspeed valve switch circuit in the FMU (4000KC)
Ref. ASM 73-25-18:
1 Make sure that contacts L and K are not shorted to ground.
2 Make sure that contacts L and K are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact L to contact K is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect the electrical connector (4000KS-J8) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel B harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
Overspeed Valve Switch Circuit Channel B Harness
FMU (4000KC) EEC (4000KS)
(4000KC-C) (4000KS-J8)
Contacts Contacts
L Y
K Z
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym OSPXCF, return the engine to the service.
2 If the test gives the fault acronym OSPXCF, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If the fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
Subtask 73-22-00-810-194-A
D. Fault Isolation for Fault Acronym OSFFMU
An overspeed valve fault was found in channel A or B. The circuit for the overspeed valve is in the open or
closed position due to a short-to-ground, or has a wire-to-wire short.
NOTE: At any time during this procedure, you can do the steps in Para. 3 to make sure that the fault is
corrected.
NOTE: The removal and installation of the electrical connectors can correct this fault.
PRE SB73-0222: PROVIDE A NEW EEC WITH SCN21/AA SOFTWARE
(1) If the fault was found in channel A, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J2) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace it as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-B) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel A overspeed valve switch circuit in the FMU (4000KC)
Ref. ASM 73-25-18:
1 Make sure that contacts L and K are not shorted to ground.
2 Make sure that contacts L and K are not shorted to any other contacts in the connector.
3 Make sure that resistance from contact L to contact K is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect electrical connector (4000KS-J2) from the EEC (4000KS)
Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel A harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
Overspeed Valve Switch Circuit Channel A Harness
FMU (4000KC) EEC (4000KS)
(4000KC-B) (4000KS-J2)
Contacts Contacts
L Y
K Z
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym OSFFMU, return the engine to the service.
2 If the test gives the fault acronym OSFFMU, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
(2) If the fault was found in channel B, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J8) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 .
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-C) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each socket. You must
feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the channel B overspeed valve switch circuit in the FMU (4000KC)
Ref. ASM 73-25-18:
1 Make sure that contacts L and K are not shorted to ground.
2 Make sure that contacts L and K are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact L to contact K is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) If no problems were found, disconnect the electrical connector (4000KS-J8) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(e) Do this electrical check of the switch wiring in the channel B harness. Look for:
1 Wire-to-wire shorts and shorts-to-ground
· Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
· Wire-to-ground short check: Measure the resistance between the wire and the engine
metal or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted
to ground and needs to be repaired.
2 Continuity
· Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector as specified
in the wiring diagram.
Overspeed Valve Switch Circuit Channel B Harness
FMU (4000KC) EEC (4000KS)
(4000KC-C) (4000KS-J8)
Contacts Contacts
L Y
K Z
3 If a problem exists with the harness, repair or replace it as necessary Ref. ASM 73-25-18.
(f) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(g) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym OSFFMU, return the engine to the service.
2 If the test gives the fault acronym OSFFMU, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-000-010 .
3 If the fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
END OF PRE SB 73-0222
POST SB 73-0222: PROVIDE A NEW EEC WITH SCN21/AA SOFTWARE
(3) Do the troubleshooting in (Ref. TSM TASK 73-22-00-810-839)
END OF POST SB 73-0222
Subtask 73-22-00-810-211-A
E. Fault Isolation for Fault Acronym WOFWAF, the Fault Acronym WONWAF, the Fault Acronym WOFWAI
and the Fault Acronym WONWAI
(Ref. Fig. Fuel Shut-Off Valve SHEET 1)
A torque motor Wrap Around Fault (WAF) was found in channel A or B. The circuit for the FMU (4000KC)
is open, short-to-ground, or has a wire-to-wire short.
NOTE: At any time during this procedure, you can do the steps in Para. 3 to make sure that the fault is
corrected.
NOTE: The removal and installation of the electrical connectors can correct this fault.
(1) Do the wiring check that follows from the FMU (4000KC) to the engine master control:
(a) Visually examine the harness from the engine master control to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 :
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) If no problems are found with the harness, disconnect the electrical connector (4000KC-A) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(c) Do this electrical check of the engine master control shut-off valve torque motor circuit in the
FMU (4000KC) Ref. ASM 76-12-01.
1 Make sure that contacts 1 and 2 are not shorted to ground.
2 Make sure that contacts 1 and 2 are not shorted to any other contacts in the connector.
3 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(d) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(e) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WOFWAF, the fault acronym WONWAF, the fault
acronym WOFWAI or the fault acronym WONWAI, return the engine to service.
2 If the test gives the fault acronym WOFWAF, the fault acronym WONWAF, the fault acronym
WOFWAI or fault acronym WONWAI, continue the troubleshooting.
(2) If the fault was found in Channel A, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J2) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 :
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) Visually examine the harness from the EEC connector (4000KS-J3) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 >.
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(c) If no problems are found with the harness, disconnect the electrical connector (4000KC-B) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(d) Do this electrical check of the channel A microswitch circuit in the FMU (4000KC) Ref. ASM
76-12-01.
1 Make sure that contacts N and M are not shorted to ground.
2 Make sure that contacts N and M are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact N to contact M is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(e) Do this electrical check of the channel A torque motor circuit in the FMU (4000KC) Ref. ASM
76-12-01.
1 Make sure that contacts P and S are not shorted to ground.
2 Make sure that contacts P and S are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact P to contact S is between 48 and 242 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(f) If no problems were found, disconnect the electrical connector (4000KS-J2) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(g) If no problems were found, disconnect the electrical connector (4000KS-J3) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(h) Do this electrical check of the microswitch and torque motor wiring in the Channel A harness.
Look for:
1 Wire-to-wire shorts and shorts-to-ground
a Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
b Wire-to-ground short check: Measure the resistance between the wire and engine metal
or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted to
ground and needs to be repaired.
2 Continuity
a Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector
as specified in the wiring diagram.
Microswitch Circuit Channel A Harness
FMU (4000KC) EEC (4000KS)
4000KC-B 4000KS-J2
Contacts Contacts
N B
M C
Torque Motor Circuit Channel A Harness
FMU (4000KC) EEC (4000KS)
4000KC-B 4000KS-J3
Contacts Contacts
P W
S V
3 If a problem exists with the harness, repair or replace as necessary Ref. ASM 76-12-01.
(i) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(j) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WOFWAF, the fault acronym WONWAF, the fault
acronym WOFWAI or the fault acronym WONWAI, return the engine to service.
2 If the test gives the fault acronym WOFWAF, the fault acronym WONWAF, the fault acronym
WOFWAI or the fault acronym WONWAI, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If the fault continues, replace CTL SW-ENG/MASTER 1 ( 3KC ) on the 115VU Ref.
ESPM 20-45-21.
a Do a test program after the removal and installation of the VU panel Ref.
AMM 31-10-00-700-001 .
4 If the fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
(3) If the fault was found in Channel B, do the following steps:
(a) Visually examine the harness from the EEC connector (4000KS-J8) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 :
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(b) Visually examine the harness from the EEC connector (4000KS-J9) to the FMU (4000KC) Ref.
AMM 71-50-00-210-010 :
1 Look for harness damage.
2 Look for loose or damaged connectors.
3 Look for loose or damaged backshells.
NOTE: Loose backshells must be disassembled and examined for internal wire chafing.
4 If a problem exists with the harness, repair or replace as necessary.
(c) If no problems are found with the harness, disconnect the electrical connector (4000KC-C) from
the FMU (4000KC) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the
connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(d) Do this electrical check of the channel B microswitch circuit in the FMU (4000KC) Ref. ASM
76-12-01.
1 Make sure that contacts N and M are not shorted to ground.
2 Make sure that contacts N and M are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact N to contact M is between 0 and 10 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(e) Do this electrical check of the channel B torque motor circuit in the FMU (4000KC) Ref. ASM
76-12-01.
1 Make sure that contacts P and S are not shorted to ground.
2 Make sure that contacts P and S are not shorted to any other contacts in the connector.
3 Make sure that the resistance from contact P to contact S is between 48 and 242 ohms.
4 If a problem was found, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
(f) If no problems were found, disconnect the electrical connector (4000KS-J8) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(g) If no problems were found, disconnect the electrical connector (4000KS-J9) from the EEC
(4000KS) Ref. AMM 71-50-00-210-010 . Examine the male and female parts of the connection:
1 Examine the pins and sockets (contacts) for alignment and damage.
2 Look for contacts pushed rearward into the connector face.
3 Look for elongated sockets in the connector.
NOTE: This can be done by inserting a harness connector pin into each suspect socket. You
must feel friction when inserting and removing the pin.
4 Repair as necessary.
(h) Do this electrical check of the microswitch and torque motor wiring in the Channel B harness.
Look for:
1 Wire-to-wire shorts and shorts-to-ground
a Wire-to-wire short check: Measure the resistance between the wires. If the resistance is
below 100000 (100K) ohms, then the wires are shorted and need to be repaired.
b Wire-to-ground short check: Measure the resistance between the wire and engine metal
or ground. If the resistance is below 100000 (100K) ohms, then the wire is shorted to
ground and needs to be repaired.
2 Continuity
a Continuity check: Measure the resistance between the ends of the same wire. If the
resistance is above 10 ohms, then the wire needs to be repaired.
NOTE: An incorrectly wired harness can cause this problem. When testing these circuits,
make sure that the contacts are in the correct positions in each connector
as specified in the wiring diagram.
Microswitch Circuit Channel B Harness
FMU (4000KC) EEC (4000KS)
4000KC-C 4000KS-J8
Contacts Contacts
N B
M C
Torque Motor Circuit Channel B Harness
FMU (4000KC) EEC (4000KS)
4000KC-C 4000KS-J9
Contacts Contacts
P W
S V
3 If a problem exists with the harness, repair or replace as necessary Ref. ASM 76-12-01.
(i) Install all the removed connectors Ref. AMM 70-23-15-912-010 .
(j) Do the test for this fault, listed in Para. 3 for fault confirmation.
1 If the test does not give the fault acronym WOFWAF, the fault acronym WONWAF, the fault
acronym WOFWAI or fault acronym WONWAI, return the engine to service.
2 If the test gives the fault acronym WOFWAF, the fault acronym WONWAF, the fault acronym
WOFWAI or fault acronym WONWAI, remove and replace the FMU ( 4000KC ) Ref.
AMM 73-22-52-000-010 and Ref. AMM 73-22-52-400-010 .
3 If the fault continues, replace CTL SW-ENG/MASTER 1 ( 3KC ) on the 115VU Ref.
ESPM 20-45-21.
a Do a test program after the removal and installation of the VU panel Ref.
AMM 31-10-00-700-001 .
4 If this fault continues, remove and replace the EEC ( 4000KS ) Ref.
AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
5. Close-up
Subtask 73-22-00-860-199-A
A. Put the aircraft back to its initial configuration.
(1) Make sure that the thrust reverser halves are closed Ref. AMM 78-32-00-410-010
(2) Make sure that the thrust reverser HCU is activated Ref. AMM 78-30-00-440-012 .
(3) Make sure that the fan cowls are closed Ref. AMM 71-13-00-410-010 .
(4) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
Ref. AMM 31-60-00-860-002 .
(5) On the ENG section of maintenance panel 50VU, push the FADEC GND PWR 1 pushbutton switch.
(6) De-energize the aircraft electrical circuits
Ref. AMM 24-41-00-862-002 .
(7) Remove the warning notice(s). [Rev.6 from Feb 2017] 2026.04.04 04:36:18 UTC