Unwanted Operation of the Power Transfer Unit (PTU) during the Start of the Engines

TASK 29-23-00-810-809-A
Unwanted Operation of the Power Transfer Unit (PTU) during the Start of the Engines

1. Possible Causes

RELAY-ENG/MASTER 1 [11QG]
RELAY-ENG/MASTER 2 [12QG]
C/B-HYDRAULIC/SOL VALVES/G/Y/PTU [1801GL]
RELAY-LDG CTL [1805GL]
RELAY-N/W STRG DE-ACT [1806GL]
RELAY-PARK BRAKE CTL [1804GL]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 29-23-00-810-801-A	Fault of the Power Transfer Unit (PTU)
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 29-23-00-710-002	Functional Check of the Power Transfer Unit (PTU) Green to Yellow
AMM 29-23-00-710-003	Functional Check of the Power Transfer Unit (PTU) Yellow to Green
AMM 29-23-00-860-002	Connection of the Isolation Coupling of the Power Transfer Unit (PTU)
ASM 292301
AMM 31-60-00-860-001	EIS Start Procedure
AMM 71-00-00-710-004	Engine Manual Start
AMM 71-00-00-710-028	Engine Shutdown

3. Fault Confirmation
Subtask 29-23-00-710-065-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(2) Make sure that the PTU P/BSW is in the AUTO position (OFF light not on).
(3) Make sure that the cargo compartment doors are not in operation with the Yellow electric hydraulic pump.
(4) Make sure that the isolation coupling of the PTU is connected AMM 29-23-00-860-002.
(5) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
(6) Do the manual start of the engines AMM 71-00-00-710-004.

NOTE: The HYD PTU FAULT message may come on at the upper ECAM DU if you do an engine start within 30 sec of an operation of the cargo doors (with the Yellow electric pump).

(7) Do a check for unwanted operation of the PTU during the engine start.

NOTE: The PTU operation is usually prevented during the engine start when:

one of the two engine master switches is set to ON
and
the parking brake is set to ON, or the nose wheel steering system is deactivated
and
the aircraft is on the ground (the nose landing gear is compressed).

(8) Shutdown the engines AMM 71-00-00-710-028.
(9) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

Subtask 29-23-00-710-065-B ** ON A/C NOT FOR ALL

NOTE: The HYD PTU FAULT message may come on at the upper ECAM DU if you do an engine start within 30 sec of an operation of the cargo doors (with the Yellow electric pump).

(7) Do a check for unwanted operation of the PTU during the engine start.

NOTE: The PTU operation is usually prevented during the engine start when:

one of the two engine master switches is set to ON
and
the parking brake is set to ON, or the nose wheel steering system is deactivated
and
the aircraft is on the ground (the nose landing gear is compressed).

(8) Shutdown the engines AMM 71-00-00-710-028.
(9) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

4. Fault Isolation
Subtask 29-23-00-810-061-A

A. If there is an unwanted operation of the PTU during the engine start, do the subsequent troubleshooting procedure:
(1) Do the operational tests of the PTU AMM 29-23-00-710-002 and AMM 29-23-00-710-003.
(a) If the operation of the PTU is not correct, do the troubleshooting of the PTU (Ref. TSM TASK 29-23-00-810-801).
(b) If the operation of the PTU is correct, find the applicable troubleshooting procedure in the subsequent steps.
(2) If at the start of the first engine, the PTU starts and stops at the start of the second engine, then replace:

the RELAY-ENG/MASTER 1 [11QG] , if the first engine started was the engine 1 ASM 292301
or
the RELAY-ENG/MASTER 2 [12QG] , if the first engine started was the engine 2 ASM 292301.

(3) If at the start of the second engine, the PTU does not start (for the auto test of the PTU), then replace:

the RELAY-ENG/MASTER 1 [11QG] , if the second engine started was the engine 1 ASM 292301
or
the RELAY-ENG/MASTER 2 [12QG] , if the second engine started was the engine 2 ASM 292301.

(4) If at the start of the first engine, the PTU starts and stays running at the start of the second engine:
(a) do a check of the circuit breaker C/B-HYDRAULIC/SOL VALVES/G/Y/PTU [1801GL] . Replace the circuit breaker C/B-HYDRAULIC/SOL VALVES/G/Y/PTU [1801GL] as necessary ASM 292301.
(b) If the fault continues:

do a check of the RELAY-LDG CTL [1805GL] . Replace the RELAY-LDG CTL [1805GL] as necessary ASM 292301.

do a check of the RELAY-N/W STRG DE-ACT [1806GL] , if the nose wheel steering system was deactivated during the engine start. Replace the RELAY-N/W STRG DE-ACT [1806GL] as necessary ASM 292301.

(d) If the fault continues:

do a check of the RELAY-PARK BRAKE CTL [1804GL] , if the parking brake was set to ON during the engine start. Replace the RELAY-PARK BRAKE CTL [1804GL] as necessary ASM 292301.

(e) If the fault continues:

do a check of the RELAY-ENG/MASTER 1 [11QG] and RELAY-ENG/MASTER 2 [12QG] . Replace the RELAY-ENG/MASTER 1 [11QG] and/or RELAY-ENG/MASTER 2 [12QG] as necessary ASM 292301.

(f) If the fault continues:
1 do a check of the wiring between the circuit breaker C/B-HYDRAULIC/SOL VALVES/G/Y/PTU [1801GL] and the SOL VALVE-PTU, G (1012GL) connector A/B ASM 292301. Repair the wiring as necessary.
2 do a check of the wiring between the circuit breaker C/B-HYDRAULIC/SOL VALVES/G/Y/PTU [1801GL] and the SOL VALVE-PTU, Y (3012GL) connector A/B ASM 292301. Repair the wiring as necessary.
(g) If the fault continues:
1 do a check of the wiring that energizes these relays ASM 292301:

RELAY-ENG/MASTER 1 [11QG]
RELAY-ENG/MASTER 2 [12QG]
RELAY-PARK BRAKE CTL [1804GL]
RELAY-LDG CTL [1805GL]
RELAY-N/W STRG DE-ACT [1806GL] .

2 Repair the wiring as necessary.

Subtask 29-23-00-710-066-A

B. Do the fault confirmation procedure as given in Para. 3 to make sure that the operation is correct.

[Rev.8 from Aug 2018] 2026.04.04 04:29:29 UTC