Trane thermostat error codes – comprehensive troubleshooting guide

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If your Trane thermostat is displaying an error code, check out this Trane thermostat error codes troubleshooting guide (description and possible repairs).

It could save you $$$ (for a service call) and time…

Trane thermostat error codes- list of Trane thermostat fault codes and their explanation.

Trane thermostat error code 26

Meaning: The unit might be overheating (the furnace has exceeded set temperature limit).

Proposed fixes: Because this error occurs due to issues such as a clogged filter, blocked fan, blocked air duct, and dirty air conditioner coil, check these components and clean/clear obstacles as necessary.

Trane thermostat error code 79

Meaning: Hard lockout (low pressure switch is open).

Suggested repair: In most cases, the issue can only be resolved by resetting the unit so switch off power to both inside and outside units to have the system reset. If the problem persists, check if the low pressure switch is faulty- it causes most of the stubborn 79 error codes.

Trane thermostat error code 89

Meaning: the stat can’t “find” the cooling/heating equipment.

Action: Check for a tripped breaker/blown fuse (to your outdoor unit)- these two are common culprits for error 89. But it can be a wiring problem somewhere in the system so check the wiring too.

Trane thermostat error code 91

Meaning: This fault code may be pointing to an issue of power- low voltage line (from the furnace) may be lacking power.

What to do: The only solution here is to inspect the entire furnace to try and identify what could be causing the fault (Call a Pro if this is beyond you).

Trane thermostat error code 126

Meaning: Trane thermostat error code 126 typically signals communication malfunction between the t-stat and your furnace/AC unit

What to do: We suggest that you switch off both the furnace and your AC (and wait a couple of minutes). You then turn the units back on and see if the error clears.

Trane 184 08 error code

Meaning: Shutdown (Soft lockout situation). This indicates that the system shutdown because perhaps it is running low on refrigerant (or restrictions in the refrigeration system/metering device).

Recommended action: Cycle power and reboot the system.

Trane 950 Thermostat error codes

Trane thermostat error code 126

Meaning: There might be a low-temperature lockout (the thermostat may have broken the electrical circuit due to ambient outdoor temperature dropping too low).

Suggested fix: Try to reset the system. Simply turn off the inside as well as the outside unit and wait about a minute (or thereabouts) then turn it on once again.

Trane 1050 Thermostat error codes

Trane 1050 Thermostat error code 67.06

Meaning: 67.06 may indicate the suction temperature sensor is experiencing problems in cooling mode- it might have shorted/out of range/circuit is open.

Action: Check if the sensor is damaged and replace.


Trane Comfortlink ii Thermostat error codes

Trane Comfortlink II error code 79

Meaning: As mentioned earlier, Error Code 79 simply says “low pressure switch open”. Causes can be iced evaporator coil, clogged air filter, low refrigerant, or a defective low pressure switch.

Potential workaround: Reset the system and check if the error clears. If not, check the above-mentioned parts (evaporator coil, air filter, low pressure switch). And oh, check the refrigerant.

Trane Touch-screen Thermostat Error Codes

Error code E0

Meaning: Thermistor error.

Action: Check sensor terminals S1 & S2 for tight connection. If wires are properly connected, consider replacing the sensor. Otherwise, the thermostat should be serviced or replaced.

Error code E1 /or “–” flashes in humidity display

Meaning: Humidity reading outside of measurable range. It can also indicate a fault with humidity sensor.

Action: Try to power cycle- the internal humidity sensor may recover. And if you suspect that the issue could be caused by an external humidity sensor problem, check the Hs & Hp terminals (Don’t forget to check your remote humidity sensor for damage/malfunction). Replace if necessary.

Error code E4

Meaning: Input voltage is out of range. Range must be between 18 Vac – 32 Vac RMS.
Action: Check the thermostat’s input voltage.

Trane thermostat reset – How do I reset my Trane thermostat?

For most units, the most effective way is turning off power to the entire system and waiting about a minute (or thereabouts). You then turn it on once again.

Here now is how to specifically reset several Trane thermostat models:

How do you reset a Nexia Trane thermostat?

Follow these steps To Reset a Nexia Trane thermostat:

  1. Check that your system is idle.
  2. Next, on your thermostat, press Menu.
  3. Tap on Settings.
  4. Select Reboot and let the thermostat shut down and then restart.

How to Reset a Wifi 824/850 Trane Thermostat

How to Reset 624 Trane Thermostat (For Heat Pump System)

Watch this video to learn how to reprogram your 624 Trane Thermostat to restore normal operation after a power outage:


Trane thermostat error codes – frequently asked questions [FAQs]

How do you fix Error code E3, E7, or E5 RTC (Real Time Clock) on Trane Touch-screen Thermostat

Cycle power to your thermostat and check if it has been repaired.

Remember to set the clock (from the stat’s Home screen) before cycling power if you are tackling Error code E5 RTC (Real Time Clock)

How do I fix the E2 error on my Trane thermostat?

This may indicate an issue with the return temperature sensor. Check it and replace if necessary.

How do you clear the error code on a Trane thermostat?

First, try power cycling. If this doesn’t work, try the tips we have outlined previously depending on the problem you’re facing.

Why won’t my Trane thermostat switch on my HVAC system?

Check the settings and adjust it where necessary – Your thermostat must be properly programmed to be able to heat/cool your home.

Why won’t my Trane thermostat connect to Wi-Fi?

Reset your Wi-Fi connection and retry– the culprit is typically your Internet connection

Final words

This guide has covered the most common Trane thermostat error codes and their solutions- try the suggested repairs and see if it will help you resolve the issue that is preventing your stat from working properly.

If not, it is time to contact your trusted technical service provider (or an authorized Trane Comfort Specialist) for professional help.


Trane AC error codes and potential fixes


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