Trane UPPER LAMP 2-TIME BLINK error code

What it means

Trane's troubleshooting table lists this pattern for indoor coil thermistor or room temperature thermistor trouble. The failure-mode table says the control detects a short or open circuit in those indoor thermistor signals.

Urgency

Likely causes

1. The room-temperature thermistor circuit is open or shorted
2. The indoor-coil thermistor circuit is open or shorted
3. An indoor sensor connector, harness, or indoor board input needs service

Homeowner fix

Make sure the indoor unit has open air around it, then power cycle once if you can do that safely. Do not open the indoor cabinet or handle sensor wiring.

When to call a pro

Call a licensed HVAC technician if the 2-time blink returns. Tell them Trane identifies this as room-temperature or indoor-coil thermistor trouble.

Repair vs replace

Indoor sensor faults are usually repairable. Replacement is rarely justified unless the unit is old and combined with a failed control board or other major repair.

• Trane ML Series 9,000 BTU R-410A 115V (NTXWMT09A111AA / NTXSMT09A111AA)

  ML Series R-410A

• Trane ML Series 12,000 BTU R-410A 115V (NTXWMT12A111AA / NTXSMT12A111AA)

  ML Series R-410A

For your technician

Technician note: inspect room-temperature thermistor, indoor-coil thermistor, connector seating, harness condition, and indoor PCB sensor input. Page context: Trane maps this display to the ML Series R-410A line; source: Trane MyLinkDrive NTXWMT-A111A(B) Service Manual, Section 9 Troubleshooting; display convention: match the letter U, letter P, letter P, letter E, letter R, letter L, letter A, letter M, letter P, two, letter T, letter I, letter M, letter E, letter B, letter L, letter I, letter N, and letter K marker exactly before comparing neighboring codes.

Which systems show it

ML Series R-410A

Related troubleshooting

Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.

Related codes

Source

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