Message Name:

SBV B SUSPECT
(Service Message)

Message Code:

B3-303775

Associated CAS:

None

Left engine surge bleed valve B suspect.

[MCID 0421]
SBV B suspect.
Detection of suspect operation in SBV B.

The electronic control units (ECUs) have detected P3 pressure changes and suspect SBV B is slow to respond.

• Surge Bleed Valve (SBV) B
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. If the L or R ENGINE MINOR FAULT CAS message is shown with this fault, this is a Short Term dispatch (STD) fault and is subject to correction outlined in the Honeywell LEMM SUBTASK 5-10-00-200-003.
2. If a L or R FADEC FAIL CAS message is shown, this is a No Dispatch (ND) fault and is subject to correction outlined in the Honeywell LEMM SUBTASK 5-10-00-200-003.
3. Check for the following MDC messages displayed with the fault: X-channel bus 1A (MCID 0905), X-channel bus 1B (MCID 0906), X-channel discrete 1A (MCID 0933), X-channel discrete 1B (MCID 0934). If any of the above MCID codes are posted, correct the cross channel faults first.
4. Issues with the N1 shutoff (Broken Shaft Connector), or bleed surge valves, contact Honeywell FSR and find out about status of Dash 12 W5 harness. Ref Honeywell S/B AS907-76-9011. Most likely tied to connector pin friction or loose connector.

1. MCID 0421 fault only is present, troubleshoot using the following steps for aircraft and engine fault isolation with reference to the Light Engine Maintenance Manual TASK 72-00-00-810-064.
2. Reset and reboot the ECU to recheck the MDC MCID for the posted fault.
3. Remove the connector on the ECU 1A W4P13, ECU 1B W3P9 and inspect for burned or pushed back pins/sockets, particularly pins 54 and 49, inspect for damage, then check the following segments per the table, repair wiring if required per the wiring manual standard practices.
4. On W3P9 and W4P13 pins 54 and 49, document the resistance value down through the coil of the Solenoid A of Surge Bleed Valve A. Resistance should be 10 to 80Ω, IAW Honeywell LMM.
5. If the wiring is suspected, access W3P12 & W4P16. Check the connector and pins for damage. Consider ringing out the SBV B, particularly on pin 8 and 9 of W5J1& W5J9.
6. Check the connection on the SBV B by examining W5P6.

   From	To	Value
   W3P9 Pin 54	W3P9 Pin 49	10 to 80 Ω
   W4P13 Pin 54	W4P13 Pin 49	10 to 80 Ω
   W5J1 Pin 8	W5J1 Pin 9	10 to 80 Ω
   W5J9 Pin 8	W5J9 Pin 9	10 to 80 Ω
   W5P6 Pin 1	W5P6 Pin 2	10 to 80 Ω
   W5P6 Pin 3	W5P6 Pin 4	10 to 80 Ω

7. If the wiring is good and the valve solenoid resistance is out of limits, replace SBV B Main Surge Bleed Valve IAW AMM TASK 75-31-05-000-801, TASK 75-31-05-400-801.
8. If the wiring and SBV check good, consider swapping the A and B ECUs for the left engine, remove and replace IAW AMM TASK 76-10-05-000-801, TASK 76-10-05-400-801.