Trane Mini Split 6-TIME BLINK Error Code

Updated 2026-08-29 · review status: manual-verified Last verified: 2026-08-29

Quick answer

6-TIME BLINK on Trane mini splits means outdoor thermistor trouble - an outdoor temperature sensor was detected as shorted or open while the compressor ran. Keep the outdoor unit clear of debris and power cycle once; sensor testing and replacement are technician work.

Severity: medium · DIY difficulty: beginner

Safety

Stop here: compressor, electrical, and inverter work is technician-only. Do not open panels, test capacitors, touch wiring, connect gauges, add refrigerant, or keep resetting the system.

What 6-TIME BLINK means

Trane's troubleshooting table lists 6-TIME BLINK as outdoor thermistor trouble. The service manual says outdoor thermistors are detected as shorted or open during compressor operation, and the upper OPERATION INDICATOR lamp blinks 6 times with a 2.5-second pause.

Code meaning varies by series

  • Trane ML series (Mitsubishi-built NTXWMT/NAXWMT) service manual: Outdoor thermistor (discharge, coil, ambient, or suction sensor) short/open circuit detected; remedy is thermistor testing per 9-5 criterion tables and outdoor unit service

Causes, ranked

  1. 1. One-time sensor reading glitch that clears on reset occasional diy-ok

    Check: Power cycle once at the breaker or disconnect if you can do that safely; keep the outdoor cabinet clear of leaves and debris but do not open it.

    Fix: If the blink clears and stays clear, monitor; if it returns, schedule service.

  2. 2. Outdoor thermistor drifted out of resistance range occasional pro-only

    Check: Requires disconnecting sensors and measuring resistance against the manual's characteristics.

    Fix: Technician: identify the failed thermistor from the failure-mode recall and replace it.

  3. 3. Sensor connector or harness fault at the outdoor board occasional pro-only

    Check: Connector inspection requires opening the outdoor cabinet.

    Fix: Technician: reseat/repair connectors and wiring.

  4. 4. Outdoor control PCB misreading a good sensor occasional pro-only

    Check: Distinguishable only with PCB-level voltage checks.

    Fix: Technician: replace the outdoor electronic control PCB if sensors test good.

Related codes

trane/3-time-blink · trane/4-time-blink · trane/5-time-blink · trane/7-time-blink · trane/upper-lamp-0-5-second-blink

Commonly searched as: "trane 6-time blink" · "trane error code 6-time blink" · "trane air conditioner 6-time blink"

Sources

  • Trane error codes (upper lamp blink table) - SplitAtlas, sourced from Trane MyLinkDrive NTXWMT-A111A(B) Service Manual Section 9 — verified 2026-08-29
  • Mitsubishi Electric / American Standard NAXSMT-A111AA (Trane ML-series equivalent) Service Manual, 9-4 Troubleshooting Check Table — verified 2026-08-29