AL22
SDMO Analog Sensor Input Fault

Controller shows AL22 indicating sensor failure (generic analog input fault).

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Open circuit in sensor wiring, Short circuit to ground or supply, Failed SDMO analog sensor (pressure, temperature, level), Incorrect sensor type configured in controller

How to Fix / Troubleshooting

Safety first: Turn the generator OFF and disconnect battery negative before probing sensor circuits.

  • Identify the sensor: Use the SDMO controller menu or manual to determine which sensor is associated with AL22 (e.g., coolant temp, oil pressure).
  • Inspect wiring: Follow the sensor harness from the sensor to the controller. Repair any visible damage and ensure connectors are fully seated.
  • Measure sensor resistance/voltage: Compare readings to SDMO specifications. Replace the sensor if values are out of range.
  • Check controller configuration: Confirm that the correct sensor type and range are selected in the controller settings.
  • Reset AL22: After repairs, clear the alarm and verify stable sensor readings.
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Repair Difficulty

Medium 3/5

Required Part

Coolant Temperature Sensor
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