Trane / American Standard Outdoor Code 67 — Low Outdoor Ambient Lockout
Code 67 on many Trane communicating systems is a low outdoor ambient lockout — the outdoor unit refuses to run cooling (or heating, depending on configuration) because outdoor temperature is outside the allowed range. It is often informational, not a failed part.
Updated July 2026 · 5 min read · Canada
Symptoms
- Thermostat shows alert 67 / outdoor ambient lockout
- Indoor fan may run; outdoor unit stays off
- Often appears on cool evenings or early spring/fall
Likely causes
- Outdoor temperature below the cooling lockout setpoint
- Misconfigured ambient lockout in the communicating control
- Faulty outdoor temperature sensor (less common)
What to do
1. Check outdoor temperature vs. lockout
If it is below ~55–60°F (13–16°C) and you called for cooling, many Trane systems intentionally lock out. Wait for warmer ambient or switch to fan-only.
2. Review thermostat / control lockout settings
On XL950/1050 and similar, ambient lockouts are configurable. Do not disable heating lockouts without understanding freeze risk.
3. Inspect the outdoor sensor mounting
If ambient is clearly warm and code 67 persists, the ODT sensor may be unplugged, damaged, or reading sun-soaked values. A tech should verify resistance charts.
Stop and call a pro when
- Code 67 persists in warm weather with accurate outdoor readings
- You also see communication faults (codes in the 90s)
- The system never runs cooling in summer
Related guides
- Nest C-Wire Install — Step-by-step Nest Learning Thermostat C-wire guidance: how to tell if you need a common wire, power connector options, and Rh/Rc/W/Y/G labeling.
- ecobee Without C-Wire — How to install an ecobee smart thermostat when you have no C-wire, using the included Power Extender Kit (PEK) with G/Y/R remapping.
- Carrier Code 13 — Carrier/Bryant code 13 is a limit lockout after repeated trips. Fix airflow first, then check filters or capacitors.
- Trane Code 126 — Trane communicating code 126 outdoor fan faults: what homeowners can check safely, capacitor symptoms, and when the condenser needs a technician.
FAQ
Is code 67 a refrigerant problem?
Usually no. It is an ambient lockout. Refrigerant issues typically show different codes or poor performance when the outdoor unit is actually running.
Need a licensed tech instead?
If the guide says to stop — or the part swap did not clear the fault — get free quotes from licensed local HVAC contractors.
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