Total-Pressure Transducer (P23) Fault (131-9(A))

TASK 49-00-81-810-854-A
Total-Pressure Transducer (P23) Fault (131-9(A))

1. Possible Causes

TOTAL PRESSURE SENSOR SHOWS OUT OF RANGE
TOTAL PRESSURE AND INLET PRESSURE DISAGREE
TOTAL PRESSURE SENSOR SHOWS OUT OF RANGE LOW
TOTAL PRESSURE SENSOR SHOWS OUT OF RANGE HIGH
damage/contamination of electrical connector P23
TOTAL PRESSURE TRANSDUCER (P23)
aircraft wiring
ELECTRONIC CONTROL BOX [59KD]
TOTAL PRESSURE TRANSDUCER (8044KM)
damage/contamination of electrical connector P22
INLET PRESSURE TRANSDUCER (P22)
INLET PRESSURE TRANSDUCER (8048KM)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 49-51-17-000-002	Removal of the Transducer - Total Pressure (131-9(A))
AMM 49-51-17-400-002	Installation of the Transducer - Total Pressure (131-9(A))
AMM 49-51-21-000-001	Removal of the Transducer - APU Inlet Pressure (131-9(A))
AMM 49-51-21-400-001	Installation of the Transducer - APU Inlet Pressure (131-9(A))
ASM 496104
AMM 49-61-34-000-003	Removal of the Electronic Control Box (ECB) (131-9(A))
AMM 49-61-34-400-003	Installation of the Electronic Control Box (ECB) (131-9(A))

3. Fault Confirmation
Subtask 49-00-81-710-056-A ** ON A/C NOT FOR ALL

A. Read-out of ECB Trouble-Shooting Data
(1) Put the APU MASTER SW to the ON position.
(2) Get access to the APU LAST LEG/PREVIOUS LEG report.
(3) Push the '>'-key adjacent to the related CFDS failure message.
(4) If the MCDU menu shows
TOTAL PRESSURE SENSOR SHOWS OUT OF RANGE

do the Fault Confirmation that follows:

(a) Get access to the APU TEST menu.
(b) Push the TEST line key.
(5) If the MCDU menu shows
TOTAL PRESSURE AND INLET PRESSURE DISAGREE
or
TOTAL PRESSURE SENSOR SHOWS OUT OF RANGE LOW
or
TOTAL PRESSURE SENSOR SHOWS OUT OF RANGE HIGH

do the Fault Confirmation that follows:

(a) Put the APU MASTER SW to the ON position.
(b) Get access to the APU GND SCANNING menu.

4. Fault Isolation
Subtask 49-00-81-810-055-A ** ON A/C NOT FOR ALL

A. If the TEST menu or the APU GND SCANNING menu gives the maintenance message:

TOTAL PRESS XDCR P23

associated with Fault Code Number (FCN) 26, 28 or 29

do a check for damage/contamination of electrical connector P23 of the TOTAL PRESSURE TRANSDUCER (P23)

(1) If the electriacl connector P23 is damaged/contaminated:

do a repair/cleaning.

(2) If the electrical connector is OK:

replace the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-000-002 and AMM 49-51-17-400-002.

(a) If the fault continues:

do a check and repair of the aircraft wiring between ECB (59KD) AB/A1,A4,A2,A3 and the TOTAL PRESSURE TRANSDUCER (P23) P23/1,2,3,4 ASM 496104.

(3) If the fault continues:

replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

Subtask 49-00-81-810-166-A ** ON A/C NOT FOR ALL

B. If the TEST menu or the APU GND SCANNING menu gives the maintenance message:

TOTAL PRESS XDCR P23

associated with Fault Code Number (FCN) 27

do a check for damage/contamination of electrical connector P23 of the TOTAL PRESSURE TRANSDUCER (P23)
do a check for damage/contamination of electrical connector P22 of the INLET PRESSURE TRANSDUCER (P22)

(1) If the electriacl connector P23/P22 are damaged/contaminated:

do a repair/cleaning.

(2) If the electrical connectors are OK:

replace the TOTAL PRESSURE TRANSDUCER (P23) AMM 49-51-17-000-002 and AMM 49-51-17-400-002.

(a) If the fault continues:

replace the INLET PRESSURE TRANSDUCER (P22) AMM 49-51-21-000-001 and AMM 49-51-21-400-001.

1 If the fault continues:

replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

Subtask 49-00-81-810-055-B ** ON A/C NOT FOR ALL

C. If the TEST menu or the APU GND SCANNING menu gives the maintenance message:

TOTAL PRESS XDCR (8044KM)

associated with Fault Code Number (FCN) 26, 28 or 29

do a check for damage/contamination of electrical connector P23 of the TOTAL PRESSURE TRANSDUCER (8044KM).

(1) If the electriacl connector P23 is damaged/contaminated:

do a repair/cleaning.

(2) If the electrical connector is OK:

replace the TOTAL PRESSURE TRANSDUCER (8044KM) AMM 49-51-17-000-002 and AMM 49-51-17-400-002.

(a) If the fault continues:

do a check and repair of the aircraft wiring between ECB (59KD) AB/A1,A4,A2,A3 and the TOTAL PRESSURE TRANSDUCER (8044KM) P23/1,2,3,4 ASM 496104.

(3) If the fault continues:

replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

Subtask 49-00-81-810-166-B ** ON A/C NOT FOR ALL

D. If the TEST menu or the APU GND SCANNING menu gives the maintenance message:

TOTAL PRESS XDCR (8044KM)

associated with Fault Code Number (FCN) 27

do a check for damage/contamination of electrical connector P23 of the TOTAL PRESSURE TRANSDUCER (8044KM).
do a check for damage/contamination of electrical connector P22 of the INLET PRESSURE TRANSDUCER (8048M)

(1) If the electriacl connectors P23/P22 are damaged/contaminated:

do a repair/cleaning.

(2) If the electrical connectors are OK:

replace the TOTAL PRESSURE TRANSDUCER (8044KM) AMM 49-51-17-000-002 and AMM 49-51-17-400-002.

(a) If the fault continues:

replace the INLET PRESSURE TRANSDUCER (8048KM) AMM 49-51-21-000-001 and AMM 49-51-21-400-001.

1 If the fault continues:

replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

Subtask 49-00-81-710-057-A ** ON A/C NOT FOR ALL

E. Do the test as in Para. 3.A.(3) or 3.A.(4).

[Rev.8 from Aug 2018] 2026.04.04 04:34:36 UTC