Message Name:

HYDRAULIC QUANTITY INDICATION INVALID

On the Engine Indication and Crew Alerting System (EICAS) Hydraulic Synoptic Page (HSP), the Hydraulic Quantity Indication is in error.

• Data Acquisition Unit (DAU) 1 (A17)
• Data Acquisition Unit (DAU) 2 (A18)
• Data Acquisition Unit (DAU) 3 (A30)
• Data Acquisition Unit (DAU) 4 (A31)
• Hydraulic-System 1 Reservoir Quantity Transducer (MT139)
• Hydraulic-System 2 Reservoir Quantity Transducer (MT142)
• Hydraulic-System 3 Reservoir Quantity Transducer (MT145)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Check the INVALID hydraulic quantity indication is on the hydraulic quantity-transducer 1, 2 or 3.

   1. If hydraulic quantity indication 1 is invalid, continue with the next step.
   2. If hydraulic quantity indication 2 is invalid, go to step 7.
   3. If hydraulic quantity indication 3 is invalid, go to step 12.

2. Disconnect the connector MT139P1 from the hydraulic quantity-transducer 1. Perform a voltage check within hydraulic quantity-transducer 1 as follows:

   From	To	Expected Result	Result
   MT139P1-A	MT139P1-B	11±1 VDC

   1. If there is 11±1 VDC, go to step 4.
   2. If there is no 11±1 VDC, continue with the next step.

3. Remove the DAU 1 to get access to connector A17BP1. Perform a continuity check for an open circuit or a short circuit to ground between the Hydraulic-Quantity Transducer 1 (MT139P1) and DAU 1 (A17BP1) that follows:

   From	To	Result
   MT139P1-A	A17BP1-G3
   MT139P1-B	A17BP1-J3

   1. If there is no continuity, repair defective wiring as required and do close out.
   2. If there is continuity, continue with the next step.

4. Perform a continuity check for an open circuit or a short circuit to ground between the Hydraulic-Quantity Transducer 1 (MT139P1) and DAU 1 (A17BP1) that follow:

   From	To	Result
   MT139P1-D	A17BP1-H3

   1. If there is no continuity, repair defective wiring as required and do close out.
   2. If there is continuity, continue with the next step.

5. Perform a check for resistance within Hydraulic-Quantity Transducer 1 (MT139P1) as follows:

   From	To	Expected Result	Result
   MT139P1-A	MT139P1-D	more than 37 Ω but less than 566 Ω
   MT139P1-B	MT139P1-D	more than 37 Ω but less than 566 Ω

   1. If resistance value is out of limit, replace the hydraulic-system reservoir 1 and do close out.
   2. If resistance value is within limit, continue with the next step.

6. Perform a continuity check for a short circuit to ground within Hydraulic-Quantity Transducer 1 (MT139P1) as follows:

   From	To	Result
   MT139P1-A	Ground
   MT139P1-B	Ground
   MT139P1-D	Ground

   1. If there is continuity, replace the hydraulic-system reservoir 1 and do close out.
   2. If there is no continuity, continue with the next step.

7. Disconnect the connector MT142P1 from the hydraulic quantity-transducer 2. Perform a voltage check within hydraulic quantity-transducer 2 as follows:

   From	To	Expected Result	Result
   MT142P1-A	MT142P1-B	11±1 VDC

   1. If there is 11±1 VDC, go to step 9.
   2. If there is no 11±1 VDC, continue with the next step.

8. Remove the DAU 2 to get access to connector A18BP1. Perform a continuity check for an open circuit or a short circuit to ground between Hydraulic-Quantity Transducer 2 (MT142P1) and DAU 2 (A18BP1) that follows:

   From	To	Result
   MT142P1-A	A18BP1-G3
   MT142P1-B	A18BP1-J3

   1. If there is no continuity, repair defective wiring as required and do close out.
   2. If there is continuity, continue with the next step.

9. Perform a continuity check for an open circuit or a short circuit to ground between Hydraulic-Quantity Transducer 2 (MT142P1) and DAU 2 (A18BP1) that follow:

   From	To	Result
   MT142P1-D	A18BP1-H3

   1. If there is no continuity, repair defective wiring as required and do close out.
   2. If there is continuity, continue with the next step.

10. Perform a check for resistance between within Hydraulic-Quantity Transducer 2 as follows:

    From	To	Expected Result	Result
    MT142P1-A	MT142P1-D	more than 37 Ω but less than 566 Ω
    MT142P1-B	MT142P1-D	more than 37 Ω but less than 566 Ω

    1. If resistance value is out of limit, replace the hydraulic-system reservoir 2 and do close out.
    2. If resistance value is within limit, continue with the next step.

11. Perform a continuity check for a short circuit to ground within Hydraulic-Quantity Transducer 2 (MT142P1) as follows:

    From	To	Result
    MT142P1-A	Ground
    MT142P1-B	Ground
    MT142P1-D	Ground

    1. If there is continuity, replace the hydraulic-system reservoir 2 and do close out.
    2. If there is no continuity, continue with the next step.

12. Disconnect the connector MT145P1 from the 3 hydraulic quantity-transducer. Perform a voltage check within hydraulic quantity-transducer 3 as follows:

    From	To	Expected Result	Result
    MT145P1-A	MT145P1-B	11±1 VDC

    1. If there is 11±1 VDC, go to step 14.
    2. If there is no 11±1 VDC, continue with the next step.

13. Remove the DAU 3 to get access to connector A30BP1. Perform a continuity check for an open circuit or a short circuit to ground between Hydraulic-Quantity Transducer 3 (MT145P1) and DAU 3 (A30BP1) that follows:

    From	To	Result
    MT145P1-A	A30BP1-G3
    MT145P1-B	A30BP1-J3

    1. If there is no continuity, repair defective wiring as required and do close out.
    2. If there is continuity, continue with the next step.

14. Perform a continuity check for an open circuit or a short circuit to ground between Hydraulic-Quantity Transducer 3 (MT145P1) and DAU 3 (A30BP1) that follows:

    From	To	Result
    MT145P1-D	A30BP1-H3

    1. If there is no continuity, repair defective wiring as required and do close out.
    2. If there is continuity, continue with the next step.

15. Perform a check for resistance within the within Hydraulic-Quantity Transducer 3 as follows:

    From	To	Expected Result	Result
    MT145P1-A	MT145P1-D	more than 37 Ω but less than 566 Ω
    MT145P1-B	MT145P1-D	more than 37 Ω but less than 566 Ω

    1. If resistance value is out of limit, go to step 17.
    2. If resistance value is within limit, continue with the next step.

16. Perform a continuity check for a short circuit to ground within Hydraulic-Quantity Transducer 3 (MT145P1) as follows:

    From	To	Result
    MT145P1-A	Ground
    MT145P1-B	Ground
    MT145P1-D	Ground

    1. If there is no continuity, do close out.
    2. If there is continuity, continue with the next step.

17. Replace Hydraulic System Reservoir 3.
18. Do close out.