Fault Message:

[ACSC2-B] CKPT DUCT OVERHEAT

Fault Code:

2164518ECS

Associated CAS:

TRIM AIR FAIL
(Caution)

The Cockpit Cabin Duct has been detected in overheat condition by the right Air Conditioning System Controller (ACSC).

• Duct Temperature Sensor (DTS) 3 (E28)
• Cockpit Ventilated Temperature Sensor (B20)
• Air Conditioning System Controller (ACSC) 2 (A88)
• Cockpit Trim Air Valve (TAV) (L26)
• Junction Box (JB6)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Access CAIMS and check cockpit DTS temperature reading. (CAIMS path: SYSTEM DIAG/AIR CONDITIONING/ACSC 2B/LRU TEST/ACSC 2B/R ACSC CH. B TRIM & CABIN TEMP SENSOR DATA). It should change with cabin temp commands.

   1. If temp reading does not change, go to step 4.
   2. If temp reading change, continue with next step.

2. Select the Aux Press Switch (SDS7) from the Bleed Air Control Panel to ON and then to OFF. Make sure the cockpit TAV go full open and full close according to the switch position (refer to Air Conditioning synoptic page).
3. Swap cockpit TAV with aft/fwd TAV.

   1. If system checks are good, replace cockpit TAV and perform step 1 again.
   2. If fault remains, continue with next step.

4. Perform a wiring checks between Bleed Air Control Panel Aux Press Switch (SDS7) and JB6.

   1. If the wiring checks are not good, replace the defective associated wiring and do close out.
   2. If the wiring checks are good, continue with next step.

5. Perform continuity checks of JB6.

   1. If there is no continuity, replace JB6 and close out.
   2. If there is continuity, continue with next step.

6. Perform a wiring checks between JB6 and cockpit TAV including the ground.

   1. If the wiring checks are not good, replace the defective associated wiring and do close out.
   2. If the wiring checks are good, continue with next step.

7. Make sure power from SPDA3 is received at JB6.
8. Perform a wiring checks between SPDA3 (A15P3-B) and JB6.

   1. If the wiring checks are not good, replace the defective associated wiring and do close out.
   2. If the wiring checks are good, continue with next step.

9. Perform continuity checks of JB6.

   1. If there is no continuity, replace JB6 and close out.
   2. If there is continuity, continue with next step.

10. Perform a wiring checks between ACSC2 and cockpit duct temp sensor (DTS).

    1. If the wiring checks are not good, replace the defective associated wiring and do close out.
    2. If the wiring checks are good, continue with next step.

11. Perform a wiring checks between ACSC2 and cockpit Vent Sensor.

    1. If the wiring checks are not good, replace the defective associated wiring and do close out.
    2. If the wiring checks are good, continue with next step.

12. Swap DTS 3 with DTS 2.

    1. If system checks are good, replace DTS 3 and do close out.
    2. If fault remains, continue with next step.

13. Swap cockpit vent sensor with aft/fwd vent sensor.

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

14. Perform a wiring checks between ACSC2 and JB6.

    1. If the wiring checks are not good, replace the defective associated wiring and do close out.
    2. If the wiring checks are good, continue with next step.

15. Perform continuity checks of JB6.

    1. If there is no continuity, replace JB6 and close out.
    2. If there is continuity, continue with next step.

16. Replace ACSC 2.
17. Do close out.