Fault Message:

SHORT CIRCUIT - SURGE VALVE/WIRING

Fault Code:

4960300APU

Associated CAS:

None

The signals from the surge valve solenoid to the Full-Authority Digital Engine-Controller (FADEC) are out of the expected range. This shows a possible short-circuit in the Surge Valve Solenoid or the signal lines to the FADEC.

• Auxiliary Power Unit (APU) Full-Authority Digital Engine-Controller (FADEC) (A108)
• Surge Control Valve (MPE2)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Examine the engine branched wiring-harness for bare wiring, kinks, worn areas and other damage (WM 49-12).

   1. If there is bare wiring, kinks, worn areas or other damage, replace Engine branched wiring-harness and do close out.
   2. If there is no bare wiring, kinks, worn areas or other damage, continue with next step.

2. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, examine the surge valve (MPE2) receptacle for contamination and damage.

   1. If there is contamination or damage, go to step 10.
   2. If there is no contamination or damage, continue with next step.

3. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, perform a continuity check within the surge valve (MPE2) receptacle (WM 49-12). The resistance should measure as follows:

   From	To	Expected Result	Result
   MPE2P1-A	MPE2P1-B	38-46 ohms

   1. If the resistance is not as mentioned above, go to step 10.
   2. If the resistance is as mentioned above, continue with next step.

4. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, make sure there is no short between each of the pins A, B, and C and the connector shell of MPE2 receptacle.

   1. If shorts are found, go to step 10.
   2. If shorts are not found, continue with next step.

5. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, perform a continuity check within the MPE2P1 connector as follows:

   From	To	Result
   MPE2P1-A	MPE2P1-B

   1. If there is no continuity, replace Engine branched wiring-harness and do close out.
   2. If there is continuity, continue with next step.

6. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, make sure there is no short within the connector shell of P1 as follows:

   From	To	Result
   P802-65	P802-66

   1. If shorts are found, replace Engine branched wiring-harness and do close out.
   2. If shorts are not found, continue with next step.

7. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, perform a continuity check within the J802 connector (WM 49-61). The resistance should measure as follows:

   From	To	Expected Result	Result
   J802-65	J802-66	>1 megohm

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

8. If SHORT CIRCUIT-SURGE VALVE/WIRING still shows on the CAIMS PMAT, perform a check for continuity between each pin that follows and the shell (WM 49-61). The resistance should measure as follows:

   From	To	Expected Result	Result
   J802-65	Ground	>1 megohm
   J802-66	Ground	>1 megohm
   A108BP1-C1	Ground	>1 megohm
   A108BP1-D1	Ground	>1 megohm

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

9. Replace Surge Control Valve (MPE2).

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

10. Replace FADEC.
11. Do close out.