What It Means
Temporary anti-short-cycle power-up delay active.
Trane AC & Heat Pump
Trane AC & Heat Pump Error Code Green LED
(Fast Flash – 5x/second)
Troubleshooting guide for the Trane AC & Heat Pump system fault Green LED (Fast Flash – 5x/second).
ACLogics Fix Trane code Green LED (Fast Flash – 5x/second) See how ACLogics handles it → Fix Green LED (Fast Flash – 5x/second) step-by-step
Possible Causes
- Normal power-up or anti-short-cycle timer delay.
- Stuck delay timer or masked secondary fault.
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
Power-up (anti-short-cycle) delay — after a power interruption or a new call for cooling/heat, the control board holds the compressor off for a short fixed delay to protect it from short-cycling, signaled by a fast green flash. This is a temporary, self-clearing state, unlike Green LED Slow Flash (settled standby with no call) or Green LED Intermittent Flash (a hard lockout that will NOT clear on its own). Once the delay timer expires, the LED should drop to the medium-flash active-run rate and the compressor will start.
All Recorded Causes
No action needed — allow the unit a few minutes to complete its startup delay. If the LED stays on fast-flash well beyond a normal power-up delay and the compressor never starts, the timer may be stuck or a separate fault may be masked; power-cycle the system once, and if fast-flash with no compressor start persists, call a technician rather than continuing to reset it.
Verify Before Replacing Parts
- Confirm the exact Trane model family and ac and heat pump context before acting on a generic code description.
- Verify current draw, overload status, and control signal before condemning the compressor or drive, given that no action needed — allow the unit a few minutes to complete its startup delay.
- Look for upstream conditions such as airflow or charge issues that may be pushing the compressor into protection, and check if the LED stays on fast-flash well beyond a normal power-up delay and the compressor neve….
- After the correction, run the system long enough to confirm the ac and heat pump fault does not return under normal load.
Not sure which system this Trane code is on?
ACLogics has guided diagnostics for 36 Trane fault codes and asks the right questions to narrow it down.
