Trane Error Codes List: A Comprehensive Guide (2025)

Trane HVAC systems, renowned for their reliability and efficiency, are equipped with advanced diagnostics to help users and technicians quickly identify and address potential issues. Understanding the Trane error codes list is essential for anyone who owns, maintains, or services these systems. These error codes displayed either on the furnace control board or the thermostat, provide vital clues to the health and operation of the HVAC unit.

Each error code on a Trane HVAC system corresponds to a specific problem or operational status. Whether it’s a furnace or an air conditioner, these codes help diagnose issues ranging from common operational glitches to more serious system malfunctions. The error codes come in various formats – from flashing LED lights on the furnace control to digital messages on touch-screen thermostats.

The codes are typically indicated through a sequence of blinking lights for furnace systems. These can signal anything from normal operational statuses, like a call for heat, to critical alerts, such as system lockouts or hardware malfunctions. In air conditioning units, the Trane thermostats display alphanumeric codes that can indicate communication errors, sensor malfunctions, or voltage irregularities, among other issues.

Homeowners and HVAC professionals alike must familiarize themselves with these error codes. By doing so, they can quickly identify the nature of the problem, which is the first step in troubleshooting. While some issues indicated by these codes can be resolved through simple DIY fixes, others may require professional intervention, especially when complex components or safety issues are involved.

The following sections will delve into the specific Trane error code list for furnaces and air conditioning units. This knowledge is not just about fixing immediate problems; it’s also about ensuring your Trane HVAC system’s long-term efficiency, reliability, and safety.

Trane Furnace Error Codes

Trane furnace systems use flashing codes on the furnace control to indicate specific issues or operational states.

Here are some of the most common codes you might encounter with your trane gas furnace:

• Flashing Slow: This indicates a normal state with no call for heat.
• Flashing Fast: Another normal operational state, but this time with a call for heat.
• Continuous ON: This suggests replacing the Integrated Furnace Control (IFC).
• Continuous OFF: This indicates an issue with the power supply to the furnace and should be checked.
• 2 Flashes: The system is in lockout mode, either due to exceeding the number of retries or recycle limits.
• 3 Flashes: This denotes a Draft Pressure Error, possibly due to various issues such as venting problems, a pressure switch malfunction, or an inducer problem.
• 4 Flashes: This is an indication of an Open High Limit Device.
• 5 Flashes: This code means that flame is sensed when no flame should be present, indicating a potential safety issue.
• 6 Flashes: This code suggests either 115 Volt AC power is reversed or there is poor grounding.
• 7 Flashes: Indicates a gas valve circuit error.
• 8 Flashes: This signals a low flame sense signal.
• 9 Flashes: This code requires a check of the Ignitor circuit and the Line “N” to 24VAC “Common” voltage, which should be less than 2 volts, pointing to a possible grounding problem.

Trane Air Conditioner Error Codes

Trane thermostats are designed to provide clear and concise error codes to help homeowners and technicians quickly identify issues. When your air conditioner encounters a problem, the thermostat will display a specific code or message. This is particularly helpful as it provides a more direct and understandable indication of the issue than interpreting flashing lights.

In addition to furnace error codes, Trane heat pump and air conditioners communicate operational issues and malfunctions through specific error codes. These Trane error code lists are typically displayed on the Trane thermostat.

Some common error codes that may appear on your Trane thermostat include:

Error Code 26

• Meaning: The unit may be overheating (exceeding the set temperature limit).
• Suggested Fix: Check for a clogged filter, blocked fan, obstructed air duct, or dirty air conditioner coil. Clean or clear any blockages as necessary.

Error Code 79

• Meaning: Hard lockout due to the low-pressure switch being open.
• Suggested Fix: Reset the unit by turning off the power to both the inside and outside units. If the issue persists, inspect for a defective low-pressure switch, a common cause of this error code.

Error Code 89

• Meaning: The thermostat can’t “find” the cooling/heating equipment.
• Suggested Fix: Check for a tripped breaker or blown fuse to your outdoor unit, as these are common causes. Also, inspect the wiring for potential issues.

Error Code 91

• Meaning: This code might indicate a power issue, such as a low-voltage line from the furnace lacking power.
• Suggested Fix: Inspect the entire furnace to locate the issue. Consider calling a professional if this task is beyond your expertise.

Error Code 126

• Meaning: This typically signals a communication malfunction between the thermostat and your furnace/AC unit.
• Suggested Fi: Turn off your heater and air conditioner, wait a few minutes, then turn them back on to see if the error clears.

Trane 950 Thermostat Error Code 126

• Meaning: Possible low-temperature lockout (thermostat may have broken the electrical circuit due to low outdoor temperature).
• Suggested Fix: Reset the system by turning off the inside and outside units, wait about a minute, then turn them on again.

Trane 1050 Thermostat Error Code 67.06

• Meaning: This code may indicate issues with the suction temperature sensor in cooling mode (it might be shorted, out of range, or have an open circuit).
• Suggested Fix: Check for any damage to the sensor and replace it if necessary.

Trane Touch-screen Thermostat Error Code E0

• Meaning: Thermistor error.
• Suggested Fix: Check the sensor terminals S1 & S2 for a tight connection. Consider replacing the sensor if the wiring is properly connected, and the issue persists. If this does not resolve the problem, the thermostat may need to be serviced or replaced.

Trane Touch-screen Thermostat Error Code E1

• Meaning: The humidity reading is outside the measurable range, or there’s a fault with the humidity sensor.
• Suggested Fix: Start with a power cycle as the internal humidity sensor may recover. If the issue might be related to an external humidity sensor, check the HS & HP terminals. Also, inspect your remote humidity sensor for any damage or malfunction and replace it if necessary.

Trane Touch-screen Thermostat Error Code E4

• Meaning: The input voltage is out of range. The acceptable range is between 18 Vac – 32 Vac RMS.
• Suggested Fix: Verify the thermostat’s input voltage. Adjustments or repairs to the power supply may be necessary if it falls outside the specified range.

In conclusion, keeping a reference of the Trane error code list handy and responding promptly to these alerts can greatly enhance your ability to manage and maintain your HVAC system, ensuring a comfortable and safe environment in your home or business.