Message Name:

PRESSURE SWITCH OUTBD/WRG/BCU

Message Code:

3245320HA

The Brake Control Unit (BCU) detected a disagreement condition between the System 2 (Outboard) Brake Pressure Switch Channel A and Channel B.

• System 2 (SYS) Brake Pressure Switch (S7)
• Brake Control Unit (BCU) (A71)
• Associated Wiring

1. Using CAIMS, access ATA 32, BCU, BRAKE CONTROL SYSTEM DATA PAGE 21 (DISCRETE INPUT STATUS).

   1. With the hydraulic system 2 OFF, the INLET PRESSURE SWITCH for SYSTEM 2 CH A and CH B should show NO PRESSURE.
   2. Pressurize hydraulic system 2 and the INLET PRESSURE SWITCH for SYSTEM 2 CH A and CH B should show PRESSURE.

2. Re-seat the BCU, making sure it is fully and properly inserted into place.

   1. If fault indication is gone, do close out.
   2. If fault remains, continue with next step.

3. Remove the BCU. make sure hydraulic system 2 is not pressurized. Perform a continuity check as follows:

   From	To	Result
   A71AP1-15K	A71AP1-15J
   A71BP1-5A	A71BP1-4B

   1. If there is continuity, go to step 6.
   2. If there is no continuity, continue with next step.

4. Apply pressure to hydraulic system 2.
5. Perform a continuity check as follows:

   From	To	Result
   A71AP1-15K	A71AP1-15J
   A71BP1-5A	A71BP1-4B

   1. If there is continuity, go to step 8.
   2. If there is no continuity, continue with next step.

6. Perform a continuity check between the Outboard brake pressure switch S7 and BCU as follows:

   From	To	Expected Result	Result
   S7P1-1	A71AP1-15K	Continuity
   S7P1-2	A71AP1-15J	Continuity
   S7P1-4	A71BP1-5A	Continuity
   S7P1-5	A71BP1-4B	Continuity
   A71AP1-15K	Ground	Open
   A71AP1-15J	Ground	Open
   A71BP1-5A	Ground	Open
   A71BP1-4B	Ground	Open

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

7. Replace the system 2 brake pressure switch (S7). Is the fault still present?

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

8. Replace BCU.
9. Do close out.