What It Means
Loss of communication between control board and outdoor unit.
Lennox All Systems
Lennox Error Code E202
Troubleshooting guide for the Lennox system fault E202.
Possible Causes
- Wiring issue.
- Bad control board.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
Lost Communication with Outdoor Unit. The control board cannot communicate with the outdoor unit (communicating systems).
All Recorded Causes
Wiring issue, bad control board.
Verify Before Replacing Parts
- Confirm the exact Lennox model family and e-codes context before acting on a generic code description.
- Confirm board LEDs, wiring polarity, and model compatibility before replacing control boards — this Lennox fault points at wiring issue, bad control board.
- Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out the next candidate on the list.
- After the correction, run the system long enough to confirm the e-codes fault does not return under normal load.
Not sure which system this Lennox code is on?
ACLogics has guided diagnostics for 16 Lennox fault codes and asks the right questions to narrow it down.
