Trane Furnace Error Codes


Trane furnaces use a two-digit code system to indicate an error. These codes can be found on the furnace's control panel and can usually be cleared by turning the system off and then back on again.


Here's a table of some common Trane furnace error codes, their light patterns, meanings and potential issues:



Potential issues

Red light constant ON Control failure Control panel issue
Red light constant OFF Check Power Power off
2 blinks Flame failure (retries exceeded) Gas supply issue, flame rod not sensing flame, wiring issue, etc.
3 blinks Pressure switch problem Blockage in vent, condensate drain plugged, etc.
4 blinks Temperature switch problem / Over temperature limit logged Plugged filter, plugged secondary heat exchanger, ductwork issue, etc.
5 blinks

Flame sensed when no flame should be present

Leaky gas valve, stuck gas valve, defective flame sensor, etc.
6 blinks 115 VAC power reversed polarity, poor grounding Issue with line voltage polarity or wiring, etc.
7 blinks Gas valve circuit error Gas valve issue
8 blinks Low flame sense signal Flame sensor malfunction, low gas pressure, etc.
9 blinks Check igniter Check igniter