04/08/21
Message Overview:
Message Description:
Auxiliary Power Unit (APU) Electronic Control Unit (ECU) reported a open or short circuit of the APU Fuel shut-off solenoid valve.
Possible Causes:
- Fuel Shutoff Solenoid (HP8)
- Auxiliary Power Unit (APU) Electronic Control Unit (ECU) (A39)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Fuel Solenoid Valve | AMM 49-31-09-000-801 |
| Installation of the Fuel Solenoid Valve | AMM 49-31-09-400-801 |
| Removal of the Auxiliary Power Unit (APU) Electronic Control Unit (ECU) | AMM 49-61-01-000-801 |
| Installation of the Auxiliary Power Unit (APU) Electronic Control Unit (ECU) | AMM 49-61-01-400-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Dowiring check from APU ECU (A39) to the Fuel Solenoid Valve (HP8) for the following wires:
From To Result Conn. A39BP1-1C Conn. HP8P1-A Conn. A39BP1-1D Conn. HP8P1-B - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair defective wiring.
- Replace the Fuel Solenoid Valve (HP8). Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Replace APU ECU (A39).
- Do close out.