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

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

The codes below apply across common Daikin models (FTX/RX (N-series split), Aurora (cold-climate ductless), FIT (side-discharge inverter heat pump), VRV/multi-split, SkyAir). Meanings follow Daikin’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 Daikin heat pump error codes

Two-character alphanumeric malfunction codes shown on the indoor wall unit, wired/wireless remote, or system controller. The first character is the division (A = indoor unit, C/H/J = sensors, E/F = outdoor protection, L/P = inverter/electrical, U = system/communication). Diagnosis is read by pressing the Cancel/Inspection button on the remote and stepping through codes. Same code family is shared across Daikin RA (residential split/ductless), SkyAir, FIT, and VRV product lines.

Daikin heat pump error codes & what they mean

These are the Daikin 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
A1	Indoor unit PCB (control board) abnormality / defect pro repair	Defective indoor unit control board; Power supply noise or surge to indoor PCB; Loose connector on indoor board	Turn off the unit at the wall switch/breaker for one minute, then restart once; Confirm power supply is stable
A3	Drain (condensate) level control system abnormality pro repair	Blocked condensate drain line; Failed drain pump; Faulty drain float switch	Check for visible water pooling around the indoor unit and stop use if leaking
A5	Freeze-up protection control (cooling) / heating peak-cut high-pressure control activated DIY-checkable	Dirty/clogged indoor air filter; Blocked indoor airflow; Low refrigerant charge	Clean or replace the indoor air filter; Make sure indoor supply/return vents and the unit face are not blocked; Restart once after cleaning
A6	Indoor fan motor (DC motor) or related wiring abnormality pro repair	Failed indoor fan motor; Broken/short wiring to fan motor; Obstruction stopping the indoor fan wheel	Power off and confirm nothing is physically blocking the indoor fan; Restart once after power-cycle
A8	Indoor fan (AC input/PCB) power abnormality pro repair	Abnormal AC input voltage to indoor unit; Defective indoor fan PCB	Confirm household power is stable; Power-cycle once
AH	Dust collector / air-cleaning (streamer) unit abnormality DIY-checkable	Dirty or contaminated dust-collection element; Air-purifier component fault	Check and clean the air-purifier/dust filter element per the owner manual; Restart once after cleaning
C4	Indoor heat-exchanger (liquid-side) thermistor or related wiring abnormality pro repair	Disconnected or shorted indoor coil thermistor; Thermistor out of resistance range	Power-cycle the unit once
C5	Indoor gas-side / room-temperature thermistor or related abnormality pro repair	Disconnected or shorted thermistor; Thermistor out of range	Power-cycle the unit once
C9	Suction-air / remote-controller thermistor abnormality pro repair	Disconnected or shorted suction-air thermistor; Thermistor out of range	Power-cycle the unit once
E1	Outdoor unit PCB (control board) abnormality / defect pro repair	Defective outdoor control board; Power surge or noise to outdoor PCB	Turn off at the breaker for one minute and restart once; Confirm the outdoor disconnect is on
E5	OL (overload protector) activation — compressor motor overload or overheat pro repair	Restricted outdoor airflow; Dirty outdoor coil; Low refrigerant or overload condition	Clear snow, leaves, and debris from around and on top of the outdoor unit; Make sure there is at least the manufacturer-specified clearance around the outdoor unit; Restart once after clearing
E6	Compressor startup fault / compressor lock pro repair	Seized or locked compressor; Low voltage at startup; Inverter drive fault	Confirm household voltage is stable; Power-cycle once
E7	Outdoor DC fan motor fault / fan lock pro repair	Outdoor fan blade obstructed (ice/debris); Failed outdoor fan motor; Broken fan wiring	Power off and clear ice, snow, or debris jamming the outdoor fan blade; Restart once after clearing
E8	Input overcurrent detection (outdoor unit AC input) pro repair	Excessive input current; Compressor or inverter overload; Supply voltage issue	Confirm the breaker and household power are stable; Power-cycle once
EA	Four-way (reversing) valve abnormality pro repair	Failed reversing valve or coil; Valve stuck between heat/cool; Wiring fault to valve coil	None beyond a single power-cycle
F3	Abnormal discharge-pipe temperature control (compressor discharge too hot) pro repair	Low refrigerant charge; Restricted refrigerant flow / blocked expansion valve; Poor outdoor heat rejection	Clear debris/snow from the outdoor unit; Stop running the unit and call a technician — continued running can damage the compressor
F6	High-pressure control activated (in cooling) pro repair	Dirty/blocked outdoor coil; Restricted outdoor airflow; Refrigerant overcharge	Clean debris off the outdoor coil and clear surrounding obstructions; Restart once after clearing
F8	Compressor protection shutdown due to temperature abnormality in the compressor pro repair	Compressor overheating; Low refrigerant / poor lubrication; Sensor fault	Clear the outdoor unit of obstructions; Power-cycle once
H0	Compressor system sensor (voltage/current) abnormality pro repair	Faulty compressor sensing circuit; Outdoor PCB fault	Power-cycle once
H6	Compressor position-detection sensor fault (operation halted) pro repair	Inverter/compressor position-detection failure; Compressor or inverter PCB fault	Power-cycle once
H8	DC voltage/current (CT) sensor fault pro repair	Faulty current sensing circuit; Abnormal input power; Outdoor PCB fault	Confirm household power is stable; Power-cycle once
H9	Outdoor air temperature thermistor or related abnormality pro repair	Disconnected or shorted outdoor-air thermistor; Thermistor out of range	Power-cycle once
J3	Discharge-pipe thermistor or related abnormality pro repair	Disconnected or shorted discharge-pipe thermistor; Thermistor out of range or misplaced	Power-cycle once
J6	Outdoor heat-exchanger thermistor or related abnormality pro repair	Disconnected or shorted outdoor coil thermistor; Thermistor out of range	Power-cycle once
J8	Liquid-pipe / sub-cooling thermistor or related abnormality pro repair	Disconnected or shorted thermistor; Thermistor out of range	Power-cycle once
L3	Electrical-component (control) box temperature rise pro repair	Restricted outdoor airflow / blocked unit; Failed component-box cooling fan; Dirty heatsink	Clear obstructions and debris around the outdoor unit; Restart once after clearing
L4	Inverter radiation fin (heatsink) high-temperature pro repair	Blocked outdoor unit / poor heat rejection; Dirty heatsink; High ambient temperature	Clear debris and snow from around the outdoor unit; Restart once after clearing
L5	Inverter output overcurrent (DC output / instantaneous overcurrent) pro repair	Compressor fault or short; Inverter PCB fault; Compressor overload	Power-cycle once
P4	Inverter radiation fin (heatsink) thermistor or related abnormality pro repair	Disconnected or shorted heatsink thermistor; Inverter PCB fault	Power-cycle once
U0	Refrigerant shortage / low refrigerant (or electronic expansion valve fault) pro repair	Refrigerant leak / undercharge; Blocked or faulty electronic expansion valve; Closed service stop valve	Make sure outdoor unit is clear of obstructions; Stop running the unit and call a technician — running low on refrigerant can damage the compressor
U2	Power supply voltage abnormality — low-voltage (drop) or main-circuit over-voltage detection pro repair	Low or unstable household supply voltage; Voltage spike/over-voltage; Loose power wiring	Confirm the breaker is on and household voltage is stable; Power-cycle once
U4	Signal transmission failure between indoor and outdoor unit pro repair	Broken or loose indoor-outdoor signal wiring; Wrong/reversed interconnect wiring; Indoor or outdoor PCB fault	Confirm both the indoor and outdoor units have power; Power-cycle the whole system once
U5	Signal transmission failure between indoor unit and remote controller pro repair	Loose/broken remote-controller wiring; Faulty remote controller; Indoor PCB fault	Check that the wired remote is seated properly; Power-cycle once
U7	Signal transmission failure on the outdoor unit PCB (between control boards) pro repair	Internal outdoor wiring/connector fault; Outdoor PCB fault	Power-cycle once
U8	Signal transmission failure between MAIN and SUB remote controllers pro repair	Main/sub remote setting conflict; Wiring fault between controllers	Power-cycle once
UA	Indoor-outdoor unit combination fault (mismatched/unspecified units or incorrect field setting) pro repair	Indoor and outdoor units are not a matched/compatible combination; Too many indoor units connected for the outdoor capacity; Incorrect address/field setting	Power-cycle the system once (this is an installation/configuration issue — a technician must verify the unit pairing)
UF	System not set yet — check (commissioning) operation not executed, or transmission wiring not completed pro repair	Indoor-outdoor wiring not finished or miswired; Check/test operation not performed at install; Service stop valve left closed	Power-cycle once (this is a commissioning issue — the installer/technician must complete setup)
UH	System malfunction — improper transmission wiring or address setting between indoor and outdoor units pro repair	Miswired indoor-outdoor transmission wiring; Incorrect unit addressing; Indoor or outdoor PCB fault	Power-cycle once (wiring/addressing must be checked by a technician)

Daikin heat pump codes we get called for most

A1 — Indoor unit PCB (control board) abnormality / defect

Typical causes include defective indoor unit control board; power supply noise or surge to indoor pcb; loose connector on indoor board. A few things are safe to check yourself (Turn off the unit at the wall switch/breaker for one minute, then restart once; Confirm power supply is stable), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes A1 on Daikin heat pumps throughout Greater Vancouver.

C4 — Indoor heat-exchanger (liquid-side) thermistor or related wiring abnormality

Typical causes include disconnected or shorted indoor coil thermistor; thermistor out of resistance range. A few things are safe to check yourself (Power-cycle the unit once), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes C4 on Daikin heat pumps throughout Greater Vancouver.

E5 — OL (overload protector) activation — compressor motor overload or overheat

Typical causes include restricted outdoor airflow; dirty outdoor coil; low refrigerant or overload condition. A few things are safe to check yourself (Clear snow, leaves, and debris from around and on top of the outdoor unit; Make sure there is at least the manufacturer-specified clearance around the outdoor unit), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes E5 on Daikin heat pumps throughout Greater Vancouver.

A5 — Freeze-up protection control (cooling) / heating peak-cut high-pressure control activated

Typical causes include dirty/clogged indoor air filter; blocked indoor airflow; low refrigerant charge. A few things are safe to check yourself (Clean or replace the indoor air filter; Make sure indoor supply/return vents and the unit face are not blocked), but the repair is a licensed HVAC technician job. HeatLand diagnoses and fixes A5 on Daikin heat pumps throughout Greater Vancouver.

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

Most Daikin 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.

Daikin heat pump repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Daikin 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.

Daikin heat pump service areas

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

Daikin heat pump error code FAQs

Can I reset my Daikin 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 Daikin E5 code mean?

On Daikin heat pumps, E5 commonly indicates ol (overload protector) activation — compressor motor overload or overheat. 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 Daikin heat pumps you didn’t install?

Yes. HeatLand is brand-agnostic and services Daikin 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 Daikin 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 Daikin heat pump repair cost in Vancouver?

It depends on the fault. Many Daikin 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: