Fault Message:

OPEN CKT-INLET DOOR XDCR/SEC VB WRG

Fault Code:

4960317APU

Associated CAS:

APU DOOR FAIL
(Caution)

APU SHUTDOWN
(Advisory)

The Full-Authority Digital Engine-Controller (FADEC) commanded an Auxiliary Power Unit (APU) shut down because the FADEC received a signal from the Inlet-Door Rotary Transducer that was out of the expected range.

• Inlet-Door Rotary Transducer (MT5)
• Full-Authority Digital Engine-Controller (FADEC) (A108)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Check if the fault message 'FADEC CONTROLLER' is displayed on the CAIMS PMAT.

   1. If NO, go to step 3.
   2. If YES, replace the FADEC and continue with next step.

2. Check if the following CAS messages are displayed on the EICAS primary display.
   Select a CAS MessageAPU DOOR FAILAPU SHUTDOWN

   1. If NO, do close out.
   2. If YES, continue with next step.

3. Disconnect the P2 connector of the inlet-door rotary transducer (MT5) from the J804 connector. Check the P2 connector for contamination and damage.

   1. If there is a damage, go to step 12.
   2. If there is no damage, continue with next step.

4. Perform a continuity check between the pins of the connector P2 as follows:

   From	To	Expected Result	Result
   MT5P2-1	MT5P2-6	<1000 ohms
   MT5P2-6	MT5P2-4	<1000 ohms
   MT5P2-2	MT5P2-3	<1000 ohms

   1. If the resistance check is not as mentioned above, go to step 12.
   2. If t he resistance check is as mentioned above, continue with next step.

5. Perform a continuity check between each pins of the connector P2 and the grounded shell as follows:

   From	To	Expected Result	Result
   MT5P2-1	Ground	>1 megaohm
   MT5P2-6	Ground	>1 megaohm
   MT5P2-4	Ground	>1 megaohm
   MT5P2-2	Ground	>1 megaohm
   MT5P2-3	Ground	>1 megaohm

   1. If the resistance check is not as mentioned above, go to step 12.
   2. If t he resistance check is as mentioned above, continue with next step.

6. Disconnect the connector P803 at the APU firewall interface (FS1046 LHS). Perform a continuity check between the pins of the connectors as follows:

   From	To	Expected Result	Result
   P803-H	J804-1	<1 ohm
   P803-J	J804-6	<1 ohm
   P803-K	J804-4	<1 ohm
   P803-A	J804-2	<1 ohm
   P803-B	J804-3	<1 ohm

   1. If the resistance check is not as mentioned above, repair defective wiring as required and do close out.
   2. If t he resistance check is as mentioned above, continue with next step.

7. Perform a continuity check between each pins of the connector as follows:

   From	To	Expected Result	Result
   P803-H	J803-J	>1 megaohm
   P803-J	J803-K	>1 megaohm
   P803-A	J803-B	>1 megaohm

   1. If the resistance check is not as mentioned above, repair defective wiring as required and do close out.
   2. If t he resistance check is as mentioned above, continue with next step.

8. Perform a continuity check between each pins and the grounded shell as follows:

   From	To	Expected Result	Result
   P803-H	Ground	>1 megaohm
   P803-K	Ground	>1 megaohm
   P803-A	Ground	>1 megaohm
   P803-B	Ground	>1 megaohm

   1. If the resistance check is not as mentioned above, repair defective wiring as required and do close out.
   2. If t he resistance check is as mentioned above, continue with next step.

9. Disconnect the connector J803 at the APU firewall interface (FS1046 LHS) and Remove FADEC connector (A108BP1). Perform a continuity check between the pins of the connectors as follows:

   From	To	Expected Result	Result
   P803-H	A108BP1-C8	<3 ohms
   P803-J	A108BP1-B8	<3 ohms
   P803-K	A108BP1-A8	<3 ohms
   P803-A	A108BP1-A7	<3 ohms
   P803-B	A108BP1-B7	<3 ohms

   1. If the resistance check is not as mentioned above, repair defective wiring as required and do close out.
   2. If t he resistance check is as mentioned above, continue with next step.

10. Perform a continuity check between the pins of the connectors that follows:

    From	To	Expected Result	Result
    P803-H	J803-J	<1 ohm
    P803-J	J803-K	<1 ohm
    P803-A	J803-B	<1 ohm

    1. If the resistance check is not as mentioned above, repair defective wiring as required and do close out.
    2. If t he resistance check is as mentioned above, continue with next step.

11. Perform a continuity check between each pin and the grounded shell as follows:

    From	To	Expected Result	Result
    P803-H	Ground	>1 megaohm
    P803-K	Ground	>1 megaohm
    P803-A	Ground	>1 megaohm
    P803-B	Ground	>1 megaohm

    1. If the resistance check is not as mentioned above, repair defective wiring as required and do close out.
    2. If t he resistance check is as mentioned above, continue with next step.

12. Replace the Inlet Door Rotary Transducer (MT5).
13. Do close out.