E18
Napoleon
ECM Blower Communication Error
Furnace shows E18; unit may operate but with abnormal fan behavior or intermittent shutdowns
Advertisements
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.
Advertisements
Possible Causes
Loose ECM motor harness, Failed ECM module on blower motor, Faulty control board ECM communication circuit, Damaged low-voltage ECM control wiring
How to Fix / Troubleshooting
Safety first: Turn off power before working on the blower or control board.
- Inspect ECM harness: Locate the ECM blower motor and its multi-pin control harness. Disconnect and reconnect the plug to ensure a solid connection. Check for bent pins or corrosion.
- Check motor power: Verify that the ECM motor is receiving line voltage at its power connector when a fan call is present.
- Observe behavior: If the motor starts and stops erratically or never starts despite proper commands, the ECM module may be failing.
- Wiring inspection: Follow the low-voltage ECM control wires from the board to the motor. Repair any damaged insulation or loose connections.
- When to replace: Replace the ECM blower motor assembly if communication errors persist and wiring is intact. If a known-good motor still fails to communicate, the control board must be replaced.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
ECM Blower Motor
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements