AC Error Codes · Trane
Trane AC Error Codes: Four Code Systems Explained
Find your code, understand what it means, then run a guided diagnosis.
Error Code Finder
Look a code up against sourced manufacturer records. Codes we cannot source are not listed — a guessed meaning is worse than no meaning.
Trane has the most fragmented diagnostics of any brand in our research: four structurally different code systems. Some inverter split remotes show hexadecimal codes such as 0x08. Standard splits show E, F, H, L and U codes. TVR-5G VRF systems use their own outdoor and indoor sets. Communicating ducted systems show plain numbers such as 79 or 126 on the thermostat. The same characters mean different things across those systems, so identifying the system comes before looking up the code.
How do Trane error codes work?
Which table applies depends on the display. A code written like 0x08 comes from an inverter split remote. A two-character code such as H3 or U1 is a standard split code. A plain number such as 79, 89 or 126 comes from a communicating ducted system's thermostat. TVR-5G VRF systems have separate outdoor and indoor code sets, and codes such as E2 exist in more than one of these systems with different meanings.
Product families covered
-
Inverter split (hex codes)
Codes shown as 0x01 to 0x0B on the remote.
-
Standard split
E, F, H, L, U, C and P two-character codes.
-
TVR-5G VRF
Separate outdoor (E, P, H0) and indoor (E, EA, EB) sets, plus an 8–88HP range.
-
Communicating / ducted
Plain numeric codes on the thermostat display, including sub-codes such as 79.02.
Where the code is displayed — and why it matters
The same fault can be labelled differently depending on which display you read it from, so identify the display before looking the code up.
- Inverter split remote
- Hexadecimal code such as 0x04 — the hex prefix identifies the table.
- Indoor display or wall controller
- Standard split E / F / H / L / U codes.
- TVR outdoor board or indoor unit
- VRF codes; note whether the code came from the outdoor or the indoor unit, because the sets differ.
- Communicating thermostat
- Plain numbers, sometimes with a decimal sub-code such as 126.01 or 184.07.
Which Trane code system are you reading?
The code's format identifies the system:
- 0x0N
- Inverter split remote (hexadecimal set)
- E / F / H / L / U + character
- Standard split system
- E or P on a VRF unit
- TVR-5G VRF — outdoor and indoor sets are separate
- Plain number (04, 79, 126)
- Communicating ducted system thermostat
How the families differ
- E2 appears in the standard split table (anti-freezing protection), the TVR outdoor table (outdoor-to-indoor chip communication) and the VRF 8–88HP table (T1 sensor) with different meanings — the system must be identified first.
- A customer searching for a numeric Trane code such as 79 is almost certainly on a communicating ducted system, not a mini-split.
- Communicating codes can carry sub-codes: 79.02 is an escalated hard lockout of 79, and 184.07 / 184.08 are universal hard lockouts.
Trane inverter split — hexadecimal codes
Read from the inverter split's remote controller. Several of these stop the unit deliberately to protect it.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| 0x01 | Indicates eEPROM communication error — unit stops | Inverter split (hex codes) | High | B |
| 0x02 | Indicates compressor failure or refrigerant leakage — unit stops | Inverter split (hex codes) | High | B |
| 0x03 | Indicates filter choke error — clean the air filter | Inverter split (hex codes) | Low | B |
| 0x04 | Indicates indoor (room) temperature sensor error — compressor disabled in cool and dry modes | Inverter split (hex codes) | Moderate | B |
| 0x05 | Indicates outdoor temperature sensor error | Inverter split (hex codes) | Moderate | B |
| 0x06 | Indicates indoor coil sensor error — compressor disabled in cool and dry modes | Inverter split (hex codes) | Moderate | B |
| 0x08 | Indicates communication error between indoor and outdoor unit — unit stops | Inverter split (hex codes) | High | B |
| 0x09 | Indicates remote controller or thermostat low battery | Inverter split (hex codes) | Low | B |
| 0x0A | Indicates input power error — unit stops | Inverter split (hex codes) | High | B |
| 0x0B | Indicates indoor fan failure — unit stops | Inverter split (hex codes) | Moderate | B |
Trane standard split codes
Two-character codes on the indoor display or wall controller.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| E1 | Indicates indoor PCB malfunction | Standard split | High | B |
| E2 | Indicates anti-freezing protection active | Standard split | Moderate | B |
| E4 | Indicates compressor discharge high-temperature protection | Standard split | High | B |
| E5 | Indicates overcurrent protection | Standard split | High | B |
| E6 | Indicates communication malfunction between indoor and outdoor unit | Standard split | High | B |
| E8 | Indicates anti-high-temperature protection active | Standard split | Moderate | B |
| EE | Indicates storage slug (refrigerant migration) fault | Standard split | Moderate | B |
| EU | Indicates iPM temperature too high — frequency limited | Standard split | High | B |
| F1 | Indicates internal ambient temperature sensor malfunction | Standard split | Low | B |
| F2 | Indicates indoor pipe temperature sensor malfunction | Standard split | Low | B |
| H3 | Indicates compressor overload | Standard split | High | B |
| H4 | Indicates system overload | Standard split | High | B |
| H6 | Indicates indoor fan motor — no feedback signal | Standard split | Moderate | B |
| Lc | Indicates compressor startup failure | Standard split | High | B |
| U1 | Indicates compressor phase-current detection malfunction | Standard split | High | B |
| U7 | Indicates four-way valve conversion abnormal | Standard split | High | B |
| UF | Indicates zero-crossing detection abnormal | Standard split | Moderate | B |
| UH | Indicates outdoor fan motor — no feedback signal | Standard split | Moderate | B |
| C5 | Indicates jump-wire cap malfunction protection | Standard split | Low | B |
| P9 | Indicates aC contactor error | Standard split | High | B |
Trane TVR-5G VRF — outdoor codes
Read from the outdoor unit. The source table gives no severity column for the VRF sets, so no severity level is published.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| H0 | Indicates m_Home unmatching (reserved code) | TVR-5G VRF outdoor | — | B |
| E0 | Indicates eEPROM fault | TVR-5G VRF outdoor | — | B |
| E2 | Indicates communication fault between outdoor chip and indoor chip | TVR-5G VRF outdoor | — | B |
| E3 | Indicates communication error between mainboard and IR341 module | TVR-5G VRF outdoor | — | B |
| E4 | Indicates outdoor unit sensor fault | TVR-5G VRF outdoor | — | B |
| E5 | Indicates voltage protection fault | TVR-5G VRF outdoor | — | B |
| E6 | Indicates dC fan fault | TVR-5G VRF outdoor | — | B |
| E7 | Indicates heating fan fault in area A for 5 minutes | TVR-5G VRF outdoor | — | B |
| E8 | Indicates two E6 faults within 10 minutes (recovers after power-off) | TVR-5G VRF outdoor | — | B |
| P0 | Indicates cooling fin high-temperature protection | TVR-5G VRF outdoor | — | B |
| P1 | Indicates high-pressure protection | TVR-5G VRF outdoor | — | B |
| P2 | Indicates low-pressure protection | TVR-5G VRF outdoor | — | B |
| P3 | Indicates compressor current protection | TVR-5G VRF outdoor | — | B |
| P4 | Indicates discharge temperature protection | TVR-5G VRF outdoor | — | B |
| P5 | Indicates outdoor condenser high-temperature problem | TVR-5G VRF outdoor | — | B |
| P6 | Indicates iPM module protection | TVR-5G VRF outdoor | — | B |
| P7 | Indicates evaporator high-temperature problem | TVR-5G VRF outdoor | — | B |
| P8 | Indicates typhoon protection | TVR-5G VRF outdoor | — | B |
Trane TVR-5G VRF — indoor codes
Read from the indoor unit. Same fault characters as the outdoor set in places, but different meanings.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| E2 | Indicates indoor-to-outdoor communication error | TVR-5G VRF indoor | — | B |
| E4 | Indicates t-3 and T-4 temperature sensor malfunction | TVR-5G VRF indoor | — | B |
| E5 | Indicates power voltage protection problem | TVR-5G VRF indoor | — | B |
| E6 | Indicates fan protection error | TVR-5G VRF indoor | — | B |
| E7 | Indicates compressor discharge temperature sensor malfunction | TVR-5G VRF indoor | — | B |
| E9 | Indicates eEPROM malfunction | TVR-5G VRF indoor | — | B |
| EA | Indicates fan runs over 5 minutes in heating mode | TVR-5G VRF indoor | — | B |
| EB | Indicates two E6 protection events within 10 minutes | TVR-5G VRF indoor | — | B |
Trane VRF 8–88HP codes
A separately documented range within the VRF line.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| E1 | Indicates communication fault between indoor and outdoor unit | VRF 8–88HP | — | B |
| E2 | Indicates t1 sensor problem | VRF 8–88HP | — | B |
| E3 | Indicates t2 sensor problem | VRF 8–88HP | — | B |
| E4 | Indicates t2B sensor problem | VRF 8–88HP | — | B |
| E5 | Indicates outdoor unit failure problem | VRF 8–88HP | — | B |
| E6 | Indicates zero-crossing signal detection problem | VRF 8–88HP | — | B |
| E7 | Indicates eEPROM problem | VRF 8–88HP | — | B |
| E8 | Indicates pG motor fan fault | VRF 8–88HP | — | B |
Trane communicating / ducted numeric codes
Shown on the thermostat of communicating residential ducted systems. Repeated trips escalate to hard lockouts that should not be repeatedly reset.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| 04 | Indicates sensor out of range or open sensor circuit | Communicating / ducted (thermostat display) | Moderate | B |
| 18 | Indicates high-pressure fault | Communicating / ducted (thermostat display) | High | B |
| 22 | Indicates freeze protection active (also used for ignition lockout on gas furnace variants) | Communicating / ducted (thermostat display) | Moderate | B |
| 44 | Indicates discharge temperature too high | Communicating / ducted (thermostat display) | High | B |
| 46 | Indicates reversing-valve fault | Communicating / ducted (thermostat display) | High | B |
| 79 | Indicates low-pressure lockout — repeated trips escalate to a 79.02 hard lockout | Communicating / ducted (thermostat display) | High | B |
| 89 | Indicates "Equipment missing" — a component that reported at startup stopped reporting; also cited as an indoor temperature sensor error in some sources | Communicating / ducted (thermostat display) | Moderate | B |
| 126 | Indicates equipment change alert / communication failure — a component dropped off the communicating bus | Communicating / ducted (thermostat display) | Moderate | B |
| 184 | Indicates max-protection / universal hard lockout | Communicating / ducted (thermostat display) | High | B |
Before you act on a code
- Never look a Trane code up without knowing which of the four systems produced it — the same characters carry different meanings across them.
- Hard lockouts (79.02, 184.07, 184.08) are protection states, not display glitches: repeatedly resetting them hides a fault that is still present.
- Refrigerant-related codes on any Trane system are technician-only work in the UAE.
Corroborated across independent technical sources
How to identify your system
- Write the code exactly as shown, including any 0x prefix or decimal sub-code.
- Note where you read it: remote, indoor display, thermostat, or the VRF outdoor unit.
- Note whether one indoor unit or many indoor units run from the outdoor unit — many indicates the TVR VRF tables.
No code showing? Start from the symptom
Trane error codes — common questions
What does Trane error code 79 mean?
79 is a low-pressure lockout on a communicating ducted system. Repeated trips escalate it to a 79.02 hard lockout. A dirty filter or an iced coil can cause it, so those are worth checking, but the refrigerant side itself is technician-only work.
What does Trane code 126 mean?
126 is an equipment change alert or communication failure — a component that was on the communicating bus stopped reporting. One power cycle is reasonable; if it returns, the low-voltage wiring or a board needs inspection.
Why does my Trane show 0x08 and not a normal code?
Some Trane inverter splits report faults in hexadecimal on the remote. 0x08 is a communication error between the indoor and outdoor unit, and the unit stops deliberately. It belongs to the hex table only — do not read it against the standard split codes.
Does Trane code 89 mean a part is missing?
89 reports "equipment missing": a component that reported at startup stopped reporting. Some sources also cite it as an indoor temperature sensor error. Either way it points at the communicating bus or wiring rather than a mechanical failure.
Need this looked at properly?
Call or send a photo on WhatsApp and we will tell you whether it needs an inspection, and what the work involves, before anyone travels.
Sources consulted
- Trane inverter-split and standard-split fault-code documentation
- Two independently hosted Trane TVR-5G VRF technical PDFs (consistent cross-reference)
- Trane communicating-system / thermostat code references