02/12/21
Message Overview:
Message Description:
L-GP-4 bus data not received at 3-OF (L-FADEC, R-FADEC, L-GPS, WXR) Or L-GP-4 bud data not received at L-GPS and WXR. Suspect failed L-GP-4 output or wiring.
Possible Causes:
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin:
- AW300-22-0007 - Nuisance IOC Message on Maintenance Diagnostic Computer
- AW300-45-0016 - MDC Nuisance Fault Messages
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Junction Box JB1 | AMM 24-63-01-000-802 |
| Installation of the Junction Box JB1 | AMM 24-63-01-400-802 |
| Removal of the Integrated Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-000-801 |
| Installation of the Integrated Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-400-801 |
| Removal of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-000-801 |
| Installation of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-400-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Field experience has revealed that the MDC may report 'NO R-GP-4 BUS OUTPUT' and/or 'NO L-GP-4 BUS OUTPUT' message(s) as current faults under ATA22-12 IAPS with or without CAS messages.
- Bombardier recommends that Operators familiarize themselves with this issue and disregard these nuisance MDC messages prior to FADEC V10B and Avionics V6.0 upgrade. ECU or wiring should be diagnosed as faulty only if other related and nonrelated systems report the GP bus invalid.
- Refer to the following documents: AW300-22-0007, AW300-45-0016.
