Trane Furnace Error Code Green Continuous / Red Flashing

This LED pattern indicates that the control board has detected either a miswired gas valve or a flame signal present before a call for heat has begun. Both conditions represent an out-of-sequence event in the ignition circuit. The furnace will not operate normally until the underlying wiring or sensor issue is resolved.

No, you should not attempt to operate the furnace while this fault is active. A miswired gas valve or an unexpected flame signal represents a safety risk, as it indicates the ignition sequence is not functioning as designed. The furnace should remain off until the cause is identified and corrected.

Repair costs depend on the root cause. If the issue is simply a miswired gas valve connection, a service call diagnostic fee may be the primary cost, typically ranging from $75 to $150. If a flame sensor or lead wire needs replacement, parts are generally low cost, but total repair costs including labor can range from $100 to $300. Control board replacement, if required, is the most expensive scenario and can range from $300 to $600 or more depending on the model.

A knowledgeable DIYer can inspect the gas valve wiring connections and compare them to the wiring diagram on the furnace cabinet for obvious miswiring. However, diagnosing a faulty flame sensor or a shorted lead wire requires a multimeter and familiarity with furnace control circuits. Because this fault involves gas valve wiring, it is recommended to have a qualified technician confirm the repair before operating the furnace.

A power reset may temporarily clear the displayed code, but the fault will return as soon as the control board detects the same condition again. Because this error is caused by a wiring or component issue rather than a momentary glitch, resetting alone will not resolve it. The underlying problem with the gas valve wiring or flame sensor circuit must be corrected first.