Fault Message:

HYD EDP 1A FAIL

Fault Code:

0000H1AF

Associated CAS:

HYD EDP 1A FAIL
(Advisory)

Data Acquisition Unit (DAU) 2 is reporting the Engine Driven Pump 1A at a pressure less than 2400 psi with the left engine running.

• Engine Driven Pump (EDP) 1A Pressure Switch (S34)
• Data Acquisition Unit (DAU) 2 (A18)
• Hydraulic Pressure Switch 1A
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Carry out a quantity check of the Hydraulic System 1.
2. Verify that the left Engine Firewall Hydraulic Shutoff Valve is physically fully open.

   1. If the left Engine Firewall Hydraulic Shutoff Valve is not fully open, perform the operational test of the left Engine Firewall Hydraulic Shutoff Valve and replace if necessary.
   2. If the left Engine Firewall Hydraulic Shutoff Valve is fully open, continue with next step.

3. Start the left Engine and check Hydraulic System 1 Pressure.

   1. If the pressure is low, replace the EDP 1 and do close out.
   2. If the pressure is good, continue with next step.

4. With the engines running, disconnect the EDP 1A Pressure Switch connector S34P1 and install a jumper between S34P1-A and S34P1-B.

   1. If the message goes away, replace the pressure switch and do close out.
   2. If the message is still shown, remove jumper and install connector S34P1 and continue with next step.

5. Swap DAU 2 with DAU 3.

   1. If system checks are good, replace DAU 2 and do close out.
   2. If fault remains, continue with next step.

6. Perform a wiring check between the EDP 1A Pressure Switch and the DAU 2.

   1. If wiring checks are not good, repair defective wiring as required and do close out.
   2. If wiring checks are good, continue with next step.

7. Do close out.