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Error code reference
Lennox Furnace Error Code E 125
Control failed self-check, internal error, failed hardware (flame sense circuit faults, pin shorts, etc.).
SourceLennox EL296DFV(X) - Service Manual: icomfort-Enabled Gas Furnacep. 11
Diagnostic procedure
The full E 125 procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Cycle power on control. Replace if problem prevents service and is persistent. Critical alert. Cleared 300 seconds after fault recovered.
SourceLennox EL296UHE - Service Manual: High-Efficiency Gas Furnacep. 12
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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Where this code is documented
3 manuals in the MyPros+ library document this code for Lennox furnace.
Models covered by the manuals that document this code
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