12/07/23
Message Overview:
Message Name:
CH A FAULT
(Service Message)
Message Code:
B3-006458
Associated CAS:
| Reporting LRU: | CKPT T SEL PNL |
| System Description: | 21-61-00 |
| Schematic Diagram: | SMM 21-61-00-101 - Temperature Control and Indication |
| Wiring Diagram: | 21-61-00 - Cabin/Cockpit Temperature Control - ALL |
Message Description:
The Channel A of the COCKPIT TEMPERATURE SELECTOR located on the bleed/air conditioning panel is detected failed.
Possible Causes:
- Cockpit Temperature Selector (CKSEL) (R02)
- Air Cond/Bleed Control Panel (PL17)
- Integrated Air System Controller (IASC1) (A55)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Fault Confirmation Procedure:
{Term Definitions}
- IAS1A-56 XX 353 00 EXCT XXXX-XXXX XXTX-XXXX XXXX-XXXX 353A: 22; COCKPIT TEMP SELECTOR A
- IAS2A-61 XX 353 10 EXCT XXXX-XXXX XXTX-XXXX XXXX-XXXX 353A: 22; COCKPIT TEMP SELECTOR B
Quick Links:
| Standard Aircraft Configuration for Maintenance | AMM 12-00-00-867-803 |
| Removal of the Integrated Air System (IAS) Controller | AMM 21-31-01-000-801 |
| Installation of the Integrated Air System (IAS) Controller | AMM 21-31-01-400-801 |
| Electrical/Electronic Safety Precautions | AMM 24-00-00-910-801 |
| Electrostatic-Discharge Safety Precautions | AMM 24-00-00-910-802 |
| Connect Electrical Power to the Aircraft | AMM 24-00-00-861-801 |
| Remove the Electrical Power from the Aircraft | AMM 24-00-00-861-802 |
| Removal of the Bleed-Air Control Panel | AMM 36-11-57-000-801 |
| Installation of the Bleed-Air Control Panel | AMM 36-11-57-400-801 |
| General | SPM20-20-00-02-01 |
| Connector Integrity After a Disconnect and Re-Connection | SPM20-20-00-02-06 |
Troubleshooting Recommendations:
- Check resistance of cockpit temp selector at connector PL17J1 between pin 33 and 35. Expected result 9.5 kΩ. If resistance value is other than 9.5 kΩ, replace the potentiometer R2.
- Check resistance of cockpit temp selector at connector PL17J1 between pin 34 and 35 while rotating the knob. Expected result, linear variant from 0 to 9.5 kΩ. If the resistance is not linear up to 9.5 kΩ replace the potentiometer R2.
- Do a continuity check between connector PL17P1 pin 35 to connector A55P2 pin 71.
- Do a continuity check between connector PL17P1 pin 34 to connector A55P2 pin 70.
- Do a continuity check between connector PL17P1 pin 33 to connector A55P2 pin 78.
- If all the above is good, swap IASC 1 with IASC 2.
- If fault follows, replace faulty IASC.