(2)  
If the maintenance message does not show on the CDU, and the status code does not show on the ISDU, then there was an intermittent fault.

(3)  
If the maintenance message shows on the CDU and the status code shows on the ISDU, then do the Fault Isolation Procedure below.

F.  Fault Isolation Procedure
(1)  For
the
applicable
DEU,
do
this
task:
CDS
BITE
Procedure,
31-62
TASK
801.

(a)  If there is a maintenance message for a DEU or EFIS control panel failure, then go to the fault isolation task for the applicable maintenance message to correct the fault.
1)  For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

2)  If the ADIRS maintenance message does not show on the CDU, and the status code does not show on the ISDU, then you corrected the fault.
3)  If the ADIRS maintenance message shows on the CDU, and the status code shows on the ISDU, then continue.
(b)  If there is no maintenance message for a DEU or EFIS control panel failure, then continue.
(2) Replace the applicable ADIRU.
These are the tasks:
Air Data Inertial Reference Unit Removal, AMM TASK 34-21-01-000-801,
Air Data Inertial Reference Unit Installation, AMM TASK 34-21-01-400-801.

(a)
Do a check of the condition of the pins and connector of the applicable ADIRU.

(b)
For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

1)  If the maintenance message does not show on the CDU, and the status code does not show on the ISDU, then you corrected the fault.
2)  If the maintenance message does show on the CDU, and the status code does show on the ISDU, then continue.
(3)  Do this check of the wiring between the applicable ADIRU and DEU:
(a)  
Remove the ADIRU. To remove it, do this task: Air Data Inertial Reference Unit Removal, AMM TASK 34-21-01-000-801.

(b)  
Remove the DEU. To remove it, do this task: Display Electronic Unit Removal, AMM TASK 31-62-21-000-801.

(c)  
For the left ADIRU, do a wiring check between these pins of connector D3975D for the DEU and connector D3687A for the ADIRU:

D3975D  D3687A
pinJ3 -------------------pinF13 pinK3 ------------------pinG13

(d)  For the right ADIRU, do a wiring check between these pins of connector D3973D for the DEU and connector D3693A for the ADIRU:
D3973D  D3693A
pinJ3 -------------------pinF13 pinK3 ------------------pinG13

(e)  If you find a problem with the wiring, then do these steps:
1) Repair the wiring.

EFFECTIVITY SIL ALL  34-21 TASK 819 
D633A103-SIL BOEING PROPRIETARY -Copyright # Unpublished Work -See title page for details  Page 239 Oct 15/2008 

TASK 31-62-21-400-801. 3) Re-install the ADIRU. To install it, do this task: Air Data Inertial Reference Unit
Installation, AMM TASK 34-21-01-400-801. 4) For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.
5) If the maintenance messages does not show on the CDU and the status code does not
show on the ISDU, then you corrected the fault.
-------------------------END OF TASK ---------------------------
820. Pitot ADM Data Invalid -Fault Isolation
A.  Description
(1)  
This task is for this maintenance message:

(a) 34-21032 PITOT ADM DATA INVLD
　
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