Lennox G60UHV Furnace Error Codes — Flash Code Diagnostic Guide

Lennox G60UHV Furnace Error Codes — What They Mean

The Lennox G60UHV is a variable-speed, 80% AFUE gas furnace that uses an ECM blower motor for quiet, efficient operation. It reports faults through a flashing LED on the control board (SureLight integrated furnace control). The LED flashes a code number, pauses, then repeats. The G60UHV also supports Lennox iComfort and Harmony III communicating thermostat systems, which can display readable fault descriptions.

Jump to Fix

Lennox G60UHV Flash Code Reference

Common Causes by Code

• Code 2 — Inducer not at speed — Unique to the G60UHV, the control board monitors inducer RPM via a Hall-effect sensor. If the inducer motor bearing is worn, the motor may start but not reach full speed. Also check for a dirty inducer wheel clogged with lint.
• Code 3 — Pressure switch open — The G60UHV uses two pressure switches in some configurations (for two-stage operation). Check both hoses and both switch contacts. A plugged condensate trap inside the unit is a common culprit.
• Code 4 — High limit — ECM blower failure is a major cause on the G60UHV. The ECM module is mounted to the rear of the motor — when the module fails, the motor runs at reduced speed or not at all, causing limit trips.
• Code 8 — Ignition lockout — SureLight ignitor (Norton/Saint-Gobain) is Lennox-specific. Do not substitute with generic ignitors — the resistance and wattage must match exactly.
• Code 9 — Rollout limit — Rollout switches are manually resetting. On the G60UHV, the rollout switches are located on the burner manifold brackets. Manual reset required after trip; do not reset without inspecting for crack in primary heat exchanger.
• Code 11 — Blower motor fault — ECM module fault or communication error between control board and motor. Try power-cycling the furnace (off 60 seconds) before replacing the motor.

Step-by-Step Fix {#fix}

1. Read the code — The G60UHV LED is on the lower control board. Open the lower door and note flash count.
2. For Code 2 — Listen to the inducer motor during startup. It should reach full speed in 15–20 seconds. If it spins slowly or makes noise, check the inducer wheel for debris and confirm the capacitor (if present) is functional.
3. For Code 3 — Check the condensate trap — it’s integrated into the cabinet on the G60UHV. Remove and flush with water. Check both pressure switch hoses (if two-stage model) for kinks or cracks.
4. For Code 4 and 12 — Replace the filter. Measure duct static pressure; anything over 0.8” W.C. is too high for the G60UHV. Verify ECM blower speed by confirming full airflow at all registers.
5. For Code 8 — Confirm SureLight ignitor is glowing during the ignition trial. If no glow, check ignitor resistance (40–90 ohms). If glowing but no flame, check gas valve coil continuity and inlet gas pressure.
6. For Code 11 — Power cycle the furnace completely. If blower doesn’t run on the next cycle, check the ECM communication connection between the control board and motor. The 5-wire communications plug is a common failure point on early G60UHV units.

Parts Often Needed

When to Call a Pro

The G60UHV’s ECM motor requires specialized diagnosis. Lennox sells a motor tester tool (L0409MOTORTOOL) used by authorized dealers to identify whether the fault is in the motor, module, or control board. If you’re seeing Code 11 or 13 without an obvious cause, an authorized Lennox dealer can connect diagnostic tools for a definitive diagnosis.

Related Articles

• Lennox Error Code 292 — Ignition Failure Fix
• Lennox EL296V Error Codes — Variable-Speed Furnace Diagnostic Guide
• Lennox Elite Series Furnace Error Codes — Fault Code Diagnostic Guide
• Lennox 103 Error Code — Causes & Fix
• Lennox Error Code 111 — Causes & Fix