Trane Heat Pump Error Codes — Meanings, Causes & Repair in Greater Vancouver

Seeing a fault code on your Trane heat pump? This guide explains what the most common Trane heat pump error codes mean, what’s safe to check yourself, and when to call HeatLand’s licensed HVAC technicians for Trane heat pump repair across Metro Vancouver and the Fraser Valley.

The codes below apply across common Trane models (ComfortLink II, XV, XR). Meanings follow Trane’s documented fault codes — always confirm against your unit’s own manual, because exact wording can vary by model, control board and firmware.

How to read Trane heat pump error codes

Trane communicating heat pumps (ComfortLink II / AccuLink, e.g. XV20i, XV18, XL18i) report alphanumeric alert codes in the form CL2.NNN.NN on the ComfortLink II thermostat (XL850/XL950/XL1050), with certain conditions also shown as a short 'ERR NN' message. The same fault on the outdoor control board is indicated by a red Fault LED flash count. The variable-speed inverter compressor 'Drive' has its own CL2.176-186 fault family. Basic single-stage units (e.g. XR14, XR15) are NON-communicating: they have no thermostat display and most show only a red outdoor-board status LED (or no diagnostic display at all). Sister brand American Standard uses the identical control platform and the same codes. Source: Trane ComfortLink II Service Facts (Pub. D802247P01) and Trane ComfortLink II Alert Codes master list.

Trane heat pump error codes & what they mean

These are the Trane heat pump codes our Greater Vancouver technicians see most. Anything marked pro repair involves electrical, refrigerant, sensor or control-board work that must be done by a licensed HVAC technician — never open the indoor/outdoor unit or refrigerant lines yourself.

Code	What it usually means	Common causes	Safe to check yourself
CL2.067.00 / 5 Flash / Fault A inputs	Ambient (outdoor air) temperature sensor fault — out of range, open or shorted. A working ambient sensor is required for defrost, low-pressure monitoring and Charge Assist, so loss of it can disable heat-pump heating/defrost pro repair	Failed outdoor ambient temperature sensor; Open or shorted sensor wiring/connector; Corroded connector at the outdoor control board	Confirm the outdoor unit disconnect and breaker are ON; Try one thermostat restart (switch the system Off, wait a minute, then back to Heat or Cool)
CL2.067.01 / 6 Flash	Coil temperature sensor fault — out of range, open or shorted. The outdoor coil sensor governs defrost timing, so a fault can cause poor heating or defrost problems pro repair	Failed outdoor coil temperature sensor; Open or shorted sensor wiring; Sensor not clipped to the coil	Confirm the outdoor disconnect and breaker are ON; Clear snow, ice, leaves and debris from around the outdoor unit; Try one thermostat restart
CL2.067.02 / 11 Flash	Liquid (line) temperature sensor fault — out of range, open or shorted pro repair	Failed liquid-line temperature sensor; Open or shorted sensor wiring/connector	Confirm the outdoor disconnect and breaker are ON; Try one thermostat restart
CL2.068.00 / 2 Flash (Defrost Fault A)	Defrost Fault A — low delta-T / low heat-pump capacity detected during the heating/defrost logic. Often points to a charge, airflow, sensor or reversing-valve issue pro repair	Reversing (switch-over) valve stuck in heat mode; Outdoor fan failure; Low refrigerant charge	Clear ice, snow, leaves and debris from the outdoor coil and fan; Confirm nothing is blocking outdoor airflow and the unit has clearance; Check and replace a dirty indoor air filter
CL2.068.01 / 3 Flash (Defrost Fault B and/or C)	Defrost Fault B and/or C — very high delta-T, or defrost terminated at least 10 times in a row on the 15-minute maximum override time instead of by temperature pro repair	Open coil sensor; Shorted ambient air sensor; Reversing valve not switching correctly	Clear ice, snow and debris from the outdoor coil; Confirm the outdoor disconnect and breaker are ON; Try one thermostat restart
CL2.068.02 / 4 Flash (Defrost Fault A and [B/C])	Combined Defrost Fault A and (B and/or C) — 60 or more A faults together with one or more B or C faults (repeated low-delta-T defrosts plus time-terminated defrosts) pro repair	Reversing valve stuck or sluggish; Low refrigerant charge; Outdoor fan or airflow problem	Clear ice, snow and debris from the outdoor coil and fan; Check and replace a dirty indoor air filter; Confirm the outdoor disconnect and breaker are ON
CL2.079.00 (LPCO Short Lock-Out)	Low-pressure cut-out open — short lock-out (about 5 minutes). Low suction pressure has tripped the switch; on the third short lock-out the control issues a hard lock-out and the thermostat shows ERR 79 pro repair	Low refrigerant charge; Refrigerant restriction; Indoor airflow restriction (cooling) — dirty filter or coil	Check and replace a dirty indoor air filter; Confirm supply/return vents are open and unobstructed; Clear ice, snow and debris from the outdoor unit
CL2.079.02 / 7 Flash / ERR 79 (LPCO Hard Lock-Out)	Low-pressure cut-out hard lock-out (Heat/Cool lockout) — low suction pressure tripped repeatedly; cycle power to reset. Note: a brief power interruption to the outdoor unit can also cause ERR 79 to display pro repair	Low refrigerant charge; Indoor airflow restriction (cooling); Outdoor airflow restriction / iced coil (heating)	Check and replace a dirty indoor air filter; Clear ice, snow and debris from the outdoor unit; Confirm the outdoor disconnect and breaker are ON
CL2.080.00 / 17 Flash / ERR 80 (HPCO Short Lock-Out)	High-pressure switch tripped — High Pressure short lock-out (HPCO limit = 650 psig). System pressure exceeded the safe limit pro repair	Refrigerant overcharge; Outdoor fan failure or outdoor airflow restriction (cooling); Indoor blower failure or indoor airflow restriction (heating)	Check and replace a dirty indoor air filter; Clear leaves, snow and debris from the outdoor unit and confirm the fan can spin freely (power off); Confirm supply/return vents are open
CL2.080.01 (HPCO Hard Lock-Out)	High-pressure hard lock-out — 6 High-Pressure short lock-out events have occurred (High-Pressure limit = 650 psig). Requires power cycle and diagnosis pro repair	Refrigerant overcharge; Outdoor fan failure / airflow restriction (cooling); Indoor blower failure / airflow restriction (heating)	Check and replace a dirty indoor air filter; Clear debris from the outdoor unit; Confirm the outdoor disconnect and breaker are ON
CL2.090.02 / 1 Flash (Alert 90)	System communication error / CRC — excessive communication errors; the comfort control is continually trying to communicate with no idle detected (bus busy) pro repair	R and B (or D and B) data wiring reversed at the thermostat or indoor unit; Faulty communicating accessory on the bus (e.g. air cleaner); Loose or damaged communication (D/B) wiring	Confirm the thermostat has power and its display is normal; Try one thermostat restart (power cycle at the breaker)
CL2.091.00 / 1 Flash / ERR 91 (Blower Comm / Loss of Demand)	Communication fault — loss of communication between control boards (e.g. blower/inducer to control board), or loss of the heat/cool demand message between the thermostat and equipment pro repair	Loss of low-voltage communication between indoor and outdoor control boards; Reversed or disconnected D/B data wiring; Power glitch affecting the low-voltage circuit	Confirm the thermostat is powered and displaying normally; Confirm the indoor and outdoor disconnects/breakers are ON; Try one thermostat restart
CL2.089.00 / CL2.089.01 (Config Fault — Equipment Missing)	Configuration fault — equipment that was auto-discovered at start-up is no longer reporting on the communication bus. Often appears after a power outage if a unit drops off the bus pro repair	Communication wiring fault (12 VDC = good, 16 VDC = loss of communication between D & B); Outdoor or indoor unit lost power; Loose data-wire connection	Confirm both indoor and outdoor disconnects/breakers are ON; Try one thermostat restart after restoring power
CL2.092.00 (Check Fuse)	Check Fuse — the 24 V fuse on the control board is open. The board Status LED is also lit solid when this condition exists pro repair	High amp draw in the low-voltage circuit; Shorted low-voltage field wiring; High resistance in field wiring	Confirm the thermostat is unresponsive/blank (a sign of a blown low-voltage fuse); Confirm the system breaker is ON
CL2.102.00 / 10 Flash (Y2 No Y1)	Y2 (second-stage) demand present without Y1 (first-stage) — a miswire condition (24-volt mode). Indicates Y1 and Y2 field wiring reversed pro repair	Y1 and Y2 thermostat/field wiring reversed; Wiring error after a thermostat change	Confirm the system breaker is ON; Try one thermostat restart
CL2.113.00 / 12 Flash / ERR 113 (Liquid Pressure Sensor Fault)	Liquid pressure sensor fault — sensor shorted (0 VDC), open (4.99 VDC) or out of range; or no output voltage from the control board pro repair	Failed liquid pressure transducer; Open or shorted sensor wiring; Control-board output voltage missing	Confirm the outdoor disconnect and breaker are ON; Try one thermostat restart
CL2.114.00 / 14 Flash / ERR 114 (Personality Module Fault)	Personality Module (PM) data fault — the primary PM data file is corrupt (system may keep running on a stored local copy, with the fault displayed on the user interface) pro repair	Corrupted Personality Module (power surge); PM damaged by faulty field wiring; PM needs replacement	Confirm the system breaker is ON; Try one thermostat restart
CL2.114.01 (Capacity Mismatch)	Personality Module fault — the outdoor-unit tonnage stored in the outdoor PM does not match the indoor PM capacity range. System runs but flags a mismatch; usually means outdoor and indoor units are not a rated match pro repair	Outdoor unit not an AHRI-rated match with the indoor unit; Wrong Personality Module installed	No homeowner action — record the code for your technician
CL2.155.00 / .01 / .02 (EEV Motor Fault)	Electronic Expansion Valve (EEV) motor fault — the EEV motor fault was detected 8 consecutive times, or the EEV motor winding/coil is open, shorted or intermittently shorted pro repair	EEV motor windings or connecting harness bad; EEV coil open or shorted	Confirm the outdoor disconnect and breaker are ON; Try one thermostat restart
CL2.174.00 (Suction Pressure Sensor Fault)	Suction pressure sensor fault — the suction pressure sensor input is shorted or out of range. (On the EEV control board this also corresponds to a 3-flash 'Suction Pressure Transducer out of range' indication.) pro repair	Failed suction pressure transducer; Open or shorted sensor wiring; No control-board output voltage to the sensor	Confirm the outdoor disconnect and breaker are ON; Try one thermostat restart
CL2.175.00 / .01 (Limp Mode)	Limp-along mode — the variable-speed compressor speed is limited to a constant value (or compressor operation is inhibited) because of a sensor loss (dome, suction, ambient or indoor sensor) or a refrigerant-pressure/airflow problem pro repair	One or more sensors faulted/out of range (dome, suction, ambient, indoor); Refrigerant pressure or airflow problem; Low charge	Check and replace a dirty indoor air filter; Clear debris from the outdoor unit; Confirm the outdoor disconnect and breaker are ON
CL2.176.00 (Drive Comm Lockout)	Modbus communication failure — loss of internal communication within the variable-speed compressor Drive. On a persistent 176.00, cycling power to the outdoor unit is advised; if it returns the Drive needs replacement pro repair	Internal Drive communication fault; Electromagnetic interference (EMI) source; Failed compressor Drive	Try one single power cycle of the outdoor unit at the breaker; Confirm the outdoor disconnect and breaker are ON
CL2.177.xx (Drive Current Failure)	Variable-speed Drive current fault — the Drive output current is too high, triggering internal derate or a current cut-out (software or hardware). Repeated occurrences cause a lockout pro repair	High load: refrigerant overcharge, dirty coils, low airflow or air recirculation; Compressor fault (locked rotor or shorted windings); Drive hardware failure	Check and replace a dirty indoor air filter; Clear leaves, snow and debris from the outdoor coil; Confirm nothing is recirculating hot air around the unit
CL2.178.00 / .01 / .02 (DC Voltage Failure)	Variable-speed Drive DC-bus voltage fault — DC bus over 480 VDC (high cut-out) or under 220 VDC (low cut-out); 10 consecutive high cut-outs cause an excessive-overvoltage lockout pro repair	Low or unstable line voltage (verify supply 187–253 VAC); PFC / Drive hardware failure	Confirm the outdoor disconnect and breaker are ON; Try one single power cycle
CL2.179.xx (Power Module Temperature Failure)	Variable-speed Drive power-module over-temperature — rectifier or inverter temperature exceeded the derate or shutdown threshold, so the compressor is derated or stopped pro repair	High load condition; Heat-sink performance loss / Drive cooling problem; Drive hardware failure	Clear debris from the outdoor unit so it can cool; Check and replace a dirty indoor air filter; Confirm the outdoor disconnect and breaker are ON
CL2.180.02 (Low Voltage Cut-Out)	Supply voltage failure — supply voltage is less than 175 VAC, causing the Drive to cut out (with derating below 200 VAC) pro repair	Low incoming line voltage / utility brown-out; Loose or undersized power wiring; Disconnect or breaker problem	Confirm the outdoor disconnect and breaker are fully ON; Try one single power cycle once normal power is confirmed
CL2.181.01 / .03 (Reverse Rotation Protection)	Reverse-rotation protection (soft/hard lock-out) — at start-up the suction pressure did not drop in the allotted time, so the compressor cannot start; 5 such shutdowns escalate to a hard lock-out. Often a reversing-valve (SOV) or compressor-pumping problem pro repair	Reversing/switch-over valve (SOV) bypassing; Compressor miswired; Suction pressure sensor failure	Confirm the outdoor disconnect and breaker are ON; Try one single power cycle
CL2.181.02 (Motor Phase Loss)	Motor phase-loss protection — a compressor cable connection or motor winding problem (a missing phase to the compressor) pro repair	Loose or damaged compressor cable connection; Compressor motor winding problem; Drive fault	Confirm the outdoor disconnect and breaker are ON; Try one single power cycle
CL2.181.04 (Stall Detection)	Stall detection — a locked-rotor condition has been detected on the variable-speed compressor pro repair	Locked-rotor compressor; Grossly overcharged system or closed service valves; Drive hardware failure	Confirm the outdoor disconnect and breaker are ON; Try one single power cycle
CL2.181.09 (No Motor)	No motor detected — the compressor motor is not detected (all three windings missing), usually a disconnected or open compressor cable pro repair	Compressor cable missing or unplugged; All compressor windings open/shorted; Drive fault	Confirm the outdoor disconnect and breaker are ON; Try one single power cycle to see if the alert clears
EEV Fault LED 6 Flash (board-level)	On the Electronic Expansion Valve control board, 6 red flashes = the valve is not responding to a position-change command (possible stuck EEV valve). Requires additional diagnostics pro repair	Stuck EEV valve; EEV motor/coil or harness fault	Confirm the outdoor disconnect and breaker are ON; Try one single power cycle
EEV Fault LED 8 Flash (board-level)	On the EEV control board, 8 red flashes = the compressor is not pumping (verify with superheat/pressure diagnostics per Service Facts) pro repair	Compressor not pumping; Low charge or restriction; Reversing valve bypassing	Confirm the outdoor disconnect and breaker are ON; Clear debris from the outdoor unit
Outdoor board LED 3 Flash (status, not a fault)	On legacy non-communicating outdoor boards, a 3-flash status indicates the unit is in an active defrost cycle — this is NORMAL operation (steam/vapor off the outdoor coil is expected), not a failure DIY-checkable	Normal cold-weather defrost cycle	No action needed — allow the unit to finish defrosting and resume heating

Trane heat pump codes we get called for most

CL2.067.00 / 5 Flash / Fault A inputs — Ambient (outdoor air) temperature sensor fault — out of range, open or shorted. A working ambient sensor is required for defrost, low-pressure monitoring and Charge Assist, so loss of it can disable heat-pump heating/defrost

Typical causes include failed outdoor ambient temperature sensor; open or shorted sensor wiring/connector; corroded connector at the outdoor control board. A few things are safe to check yourself (Confirm the outdoor unit disconnect and breaker are ON; Try one thermostat restart (switch the system Off, wait a minute, then back to Heat or Cool)), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes CL2.067.00 / 5 Flash / Fault A inputs on Trane heat pumps throughout Greater Vancouver.

CL2.091.00 / 1 Flash / ERR 91 (Blower Comm / Loss of Demand) — Communication fault — loss of communication between control boards (e.g. blower/inducer to control board), or loss of the heat/cool demand message between the thermostat and equipment

Typical causes include loss of low-voltage communication between indoor and outdoor control boards; reversed or disconnected d/b data wiring; power glitch affecting the low-voltage circuit. A few things are safe to check yourself (Confirm the thermostat is powered and displaying normally; Confirm the indoor and outdoor disconnects/breakers are ON), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes CL2.091.00 / 1 Flash / ERR 91 (Blower Comm / Loss of Demand) on Trane heat pumps throughout Greater Vancouver.

CL2.155.00 / .01 / .02 (EEV Motor Fault) — Electronic Expansion Valve (EEV) motor fault — the EEV motor fault was detected 8 consecutive times, or the EEV motor winding/coil is open, shorted or intermittently shorted

Typical causes include eev motor windings or connecting harness bad; eev coil open or shorted. A few things are safe to check yourself (Confirm the outdoor disconnect and breaker are ON; Try one thermostat restart), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes CL2.155.00 / .01 / .02 (EEV Motor Fault) on Trane heat pumps throughout Greater Vancouver.

Is it safe to keep running a Trane heat pump with a fault code?

Most Trane fault codes put the heat pump into a safe lockout for a reason. You can safely check the basics — the power and breaker on, the indoor filter clean, the outdoor unit clear of snow, ice and debris, and the remote set to the correct mode and temperature — and restart it once. If the code returns, stop and book a technician. Mini-split and heat-pump faults are electrical and refrigerant issues — never open the indoor or outdoor unit, and never touch the wiring or refrigerant lines yourself.

Trane heat pump repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Trane heat pumps — sensor and thermistor errors, indoor-to-outdoor communication faults, fan and compressor problems, refrigerant and pressure faults, and control-board issues — including units we didn’t install. We’re brand-agnostic, carry common parts, and give you an honest repair-or-replace assessment with upfront pricing and a free estimate. If your heat pump is beyond economical repair, we’ll show you right-sized, high-efficiency replacement options and the rebates available.

Need it sorted fast? We offer priority emergency heat pump repair. Explore Heat Pump services, browse all heat pump error codes by brand, or request a free estimate.

Trane heat pump service areas

We repair Trane heat pumps across Greater Vancouver and the Fraser Valley, including:

Trane heat pump error code FAQs

Can I reset my Trane heat pump myself?

Yes — power-cycling the unit at the breaker once is generally safe after you’ve checked the basics (the power and breaker on, the indoor filter clean, the outdoor unit clear of snow, ice and debris, and the remote set to the correct mode and temperature). If the heat pump faults again right away, stop and note the code — repeatedly resetting a heat pump that keeps locking out can mask a real problem. Call a licensed HVAC technician to diagnose it.

What does the Trane CL2.067.00 / 5 Flash / Fault A inputs code mean?

On Trane heat pumps, CL2.067.00 / 5 Flash / Fault A inputs commonly indicates ambient (outdoor air) temperature sensor fault — out of range, open or shorted. a working ambient sensor is required for defrost, low-pressure monitoring and charge assist, so loss of it can disable heat-pump heating/defrost. Confirm the exact meaning against your unit’s manual — codes can vary by model and series — and have the repair done by a licensed HVAC technician. HeatLand fixes this across Greater Vancouver.

Do you repair Trane heat pumps you didn’t install?

Yes. HeatLand is brand-agnostic and services Trane heat pumps throughout Metro Vancouver and the Fraser Valley, whether or not we installed the unit. We carry common parts and give you an honest repair-or-replace assessment.

Is a Trane heat pump fault code an emergency?

No heat in cold weather or no cooling in a heat wave is worth treating urgently. For priority heat pump repair across Greater Vancouver, call (604) 330-3812.

How much does Trane heat pump repair cost in Vancouver?

It depends on the fault. Many Trane codes point to sensors, thermistors, capacitors or control parts — usually far cheaper than replacement. We give upfront pricing and a free estimate before any work.

More Heat Pump error-code guides

HeatLand repairs every major heat pump brand across Greater Vancouver. More brand guides: