York TM9T100C16MP11 Error Code Continuous Amber Flash: Low Flame Sense Current
What Does Code Continuous Amber Flash Mean?
The continuous amber flash on the York TM9T100C16MP11 indicates the flame sense current is below 1.5 microamps. The flame sensor is detecting the burner flame, but the signal is weaker than the minimum required threshold. The furnace is still running but may shut down if the flame signal drops further.
The flame sensor is a thin metal rod positioned in the burner flame. It works by conducting a tiny electrical current through the flame. Over time, carbon deposits and oxidation build up on the rod, reducing the current it can conduct. The control board monitors this current and triggers the continuous amber warning when it drops below 1.5 microamps.
Insufficient gas flow is a less common but possible cause. If the gas pressure is too low, the flame may not fully envelop the sensor rod, resulting in a weaker signal even if the sensor itself is clean.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Dirty flame sensor | Most common | ✗ Call a pro → |
| Insufficient gas flow | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The continuous amber flash persists after thoroughly cleaning the flame sensor
- The furnace shuts off within seconds of igniting even with a clean sensor
- You notice the flame color is yellow or orange instead of blue
- The sensor rod is visibly pitted or corroded beyond what cleaning can restore
- You suspect a gas pressure issue (weak flame, pilot-like burner appearance)
Sources
✓ Verified against manufacturer service manual — March 2026