What causes Daikin Mini Split E6?

A locked or seized compressor, the first root cause in Daikin's E6 chart for wall-mount units. A disconnected or loose compressor harness (the U, V and W leads between the outdoor board and the compressor), Daikin's second listed cause. A defective outdoor unit PCB or a power supply problem, which Daikin's flowchart checks with an inverter analyzer before blaming the compressor. A faulty outdoor electronic expansion valve coil, which Daikin's flowchart says to check when the unit shuts down after repeated errors. On SkyAir and VRV systems: a refrigerant stop valve that was never opened, a defective control PCB, a defective connector contact, or a defective compressor, per Daikin's self-diagnosis list. On VRV systems where E6 is reported as compressor overcurrent: a defective electronic expansion valve or a shortage of refrigerant, also from Daikin's self-diagnosis list.

How do I fix Daikin Mini Split E6?

Turn the system off, switch off the breaker for the outdoor unit, wait a few minutes, then restore power and try again. A one-time start-up hiccup, for example after a brownout, can clear this way. Make sure the outdoor unit has its full supply voltage: check that the breaker or disconnect isn't half-tripped and that nobody has been working on the wiring. If E6 started right after installation or a move, call the installer. A stop valve left closed or a compressor lead left loose is an installation fix. Note when E6 appears (at start-up, after a few minutes, in cooling or heating) and whether you hear the outdoor unit hum or click without starting. That helps a technician narrow it down. If E6 comes back after a reset, stop running the unit and call a licensed HVAC technician. Repeated start attempts on a locked compressor can damage it further, and the checks involve high voltage.

When should I call a pro for Daikin Mini Split E6?

Following Daikin's E6 flowchart for wall-mount units: power off, disconnect the U, V and W compressor harnesses, and check the outdoor board's output with an inverter analyzer. If the output isn't normal, correct the power supply or replace the outdoor unit PCB. If the board output is normal, reconnecting the harnesses and restarting. If the unit makes an emergency stop without the compressor running, Daikin says to replace the compressor. If the compressor runs but the system shuts down after errors repeat several times, Daikin says to replace the compressor; if it doesn't, check the outdoor electronic expansion valve coil and replace it as required. On SkyAir and VRV units, confirming the stop valves are open, checking connector contacts and the control PCB, and checking the compressor, refrigerant charge and expansion valve as listed in Daikin's self-diagnosis code list.

Code: E6🔧 Daikin Mini Split

Daikin Error Code E6: Compressor Lock or Start-Up Abnormality (Meaning, Causes, Fixes)

Q: What does Daikin Mini Split E6 mean?

E6 on a Daikin air conditioner or heat pump means the compressor couldn't start or locked up. On Daikin wall-mount mini splits such as the Entra series, Daikin calls it "compressor lock/start-up abnormality," and the two root causes it lists are a locked compressor or a disconnected compressor harness. On SkyAir and VRV systems, E6 points to the standard (non-inverter) compressor locking or drawing too much current. Reset the power once; if E6 comes back, call a licensed HVAC technician, because the checks involve high voltage and the compressor. Daikin's Entra wall mount service manual (FTK(X)B and RK(X)B AXVJU) lists E6 as "Compressor lock/start-up abnormality" in its inverter error code table, between E5 (compressor overload) and E7 (outdoor fan motor lock). The outdoor inverter board tries to start the compressor and, when the compressor doesn't turn or won't come up to speed, it stops and shows E6. Daikin gives two possible root causes: the compressor itself is locked, or the compressor harness (the U, V and W wires from the inverter board to the compressor) is disconnected. On Daikin's light commercial and VRV equipment the code is defined a little differently: the SkyAir inverter service manual SiUS25-501 lists E6 as "Standard compressor lock or over current," and Daikin's Simple Self-Diagnosis code list describes it as STD compressor motor overcurrent or lock. In every case the unit shuts the compressor off to protect it.

Reviewed 2026-10-24 · Based on 3 manufacturer & service sources

What the code means

Daikin's Entra wall mount service manual (FTK(X)B and RK(X)B AXVJU) lists E6 as "Compressor lock/start-up abnormality" in its inverter error code table, between E5 (compressor overload) and E7 (outdoor fan motor lock). The outdoor inverter board tries to start the compressor and, when the compressor doesn't turn or won't come up to speed, it stops and shows E6. Daikin gives two possible root causes: the compressor itself is locked, or the compressor harness (the U, V and W wires from the inverter board to the compressor) is disconnected. On Daikin's light commercial and VRV equipment the code is defined a little differently: the SkyAir inverter service manual SiUS25-501 lists E6 as "Standard compressor lock or over current," and Daikin's Simple Self-Diagnosis code list describes it as STD compressor motor overcurrent or lock. In every case the unit shuts the compressor off to protect it.

Likely causes

A locked or seized compressor, the first root cause in Daikin's E6 chart for wall-mount units.
A disconnected or loose compressor harness (the U, V and W leads between the outdoor board and the compressor), Daikin's second listed cause.
A defective outdoor unit PCB or a power supply problem, which Daikin's flowchart checks with an inverter analyzer before blaming the compressor.
A faulty outdoor electronic expansion valve coil, which Daikin's flowchart says to check when the unit shuts down after repeated errors.
On SkyAir and VRV systems: a refrigerant stop valve that was never opened, a defective control PCB, a defective connector contact, or a defective compressor, per Daikin's self-diagnosis list.
On VRV systems where E6 is reported as compressor overcurrent: a defective electronic expansion valve or a shortage of refrigerant, also from Daikin's self-diagnosis list.

Safe DIY checks

⚠ Before you start

Turn off the power before touching any connector or compressor lead. The outdoor inverter board can hold a dangerous charge after power is removed. Compressor replacement and any refrigerant work must be done by a certified technician (in the US, EPA Section 608 certification is required to handle refrigerant).

Turn the system off, switch off the breaker for the outdoor unit, wait a few minutes, then restore power and try again. A one-time start-up hiccup, for example after a brownout, can clear this way.
Make sure the outdoor unit has its full supply voltage: check that the breaker or disconnect isn't half-tripped and that nobody has been working on the wiring.
If E6 started right after installation or a move, call the installer. A stop valve left closed or a compressor lead left loose is an installation fix.
Note when E6 appears (at start-up, after a few minutes, in cooling or heating) and whether you hear the outdoor unit hum or click without starting. That helps a technician narrow it down.
If E6 comes back after a reset, stop running the unit and call a licensed HVAC technician. Repeated start attempts on a locked compressor can damage it further, and the checks involve high voltage.

🛠 When to call a pro

Following Daikin's E6 flowchart for wall-mount units: power off, disconnect the U, V and W compressor harnesses, and check the outdoor board's output with an inverter analyzer. If the output isn't normal, correct the power supply or replace the outdoor unit PCB.
If the board output is normal, reconnecting the harnesses and restarting. If the unit makes an emergency stop without the compressor running, Daikin says to replace the compressor.
If the compressor runs but the system shuts down after errors repeat several times, Daikin says to replace the compressor; if it doesn't, check the outdoor electronic expansion valve coil and replace it as required.
On SkyAir and VRV units, confirming the stop valves are open, checking connector contacts and the control PCB, and checking the compressor, refrigerant charge and expansion valve as listed in Daikin's self-diagnosis code list.

Parts that commonly fix it

Always match the part number to your exact model.

⚙

Digital multimeter

Used with the power off to check the compressor leads and winding resistance.

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⚙

Electronic expansion valve coil

Only if it fails a technician's check; match the exact Daikin outdoor unit model and part number.

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⚙

Outdoor control board

Only if Daikin's inverter analyzer check shows the board output is abnormal; match the exact model.

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Sources

Last reviewed 2026-10-24. Always confirm against the manual for your exact model number.

Daikin Error Code E6: Compressor Lock or Start-Up Abnormality (Meaning, Causes, Fixes)

What the code means

Likely causes

Safe DIY checks

🛠 When to call a pro

Parts that commonly fix it

Digital multimeter

Electronic expansion valve coil

Outdoor control board

Related codes

Sources