E-18
CAT Analog Sensor Out of Range / Sensor Calibration Fault

Controller shows E-18, generator runs but alarms, possible sensor issues

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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

Failed temperature or pressure sensor, Broken sensor wiring, Incorrect sensor type installed, Controller configuration mismatch

How to Fix / Troubleshooting

Safety: Disable automatic start and allow the engine to cool if temperature-related.

  • Identify sensor: Use the controller menu to see which parameter is out of range (e.g., coolant temp, oil pressure, fuel level).
  • Inspect sensor and wiring: Locate the indicated sensor on the engine or tank. Check for loose connectors, damaged cables, or oil/coolant contamination on the connector.
  • Compare with mechanical gauge: If available, compare the controller reading with a mechanical gauge (e.g., oil pressure gauge). Large discrepancies indicate a sensor or wiring fault.
  • Check part number: Verify the installed sensor matches the CAT part number specified for the generator model.
  • Replace sensor if faulty: Install a new CAT-approved sensor and clear the E-18 code. Re-test under normal operating conditions.

If the new sensor still reads out of range, the controller input or configuration may be incorrect and should be checked by a CAT technician.

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Repair Difficulty

Medium 3/5

Required Part

Coolant Temperature Sensor
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