Outdoor Heat Exchanger Thermistor Abnormality

Home Appliance Error Codes Daikin Split AC

Can you still use it? With care until repaired

Who can fix it? Needs a technician

Typical repair time 30 minutes – 2 hours

Typical cost SAR 80 to 2,500

What it means

This code appears on Daikin split, ducted and cassette air conditioners and means the thermistor on the outdoor condenser coil is reading implausibly because of an open or short circuit. The unit uses this reading for high pressure control and for defrost in heating mode, so it stops or runs with limited performance. The same code can mean something else on other brands.

Models covered: Daikin split air conditioners and Daikin ducted/cassette (SkyAir) units, which share the same error code system; the code shows on the wired remote or via the wireless remote check function.

Symptoms3

Code J6 appears and cooling stops or weakens.
Irregular outdoor fan operation.
Depending on the model, the unit may run at reduced capacity before stopping.

Possible causes5

A loose or corroded sensor connector on the outdoor board.
A thermistor damaged by heat, moisture or cleaning chemicals.
A cut or chewed sensor wire.
The thermistor has slipped off the coil pipe after washing or service.
A faulty sensor input circuit on the board.

How to diagnose5

Switch the unit off at the breaker for a few minutes, then restart.
If the outdoor unit was washed recently, have the technician check the connector is dry and the sensor is secure.
A technician inspects the sensor, wire and connector after isolating power and discharging the board.
The technician measures the thermistor resistance against the Daikin table.
If the sensor is good and the code persists, the board's sensor input is checked.

How to fix5

Refit the sensor on the pipe and dry and clean its connector.
Repair the damaged wire.
Replace the outdoor heat exchanger thermistor, which on some models comes as part of a sensor set.
Replace the outdoor PCB if its sensor input is proven faulty.
Run the unit and confirm the code does not return.

Repair cost

0–200

200–600

600–1,500

1,500+

In Saudi riyals; the highlighted part is the expected range for this fault.

A new sensor or wire repair is relatively cheap; the top of the range applies only if the outdoor board must be replaced.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions

Why did J6 appear after the outdoor unit was washed?

Water or cleaning chemicals can get into the sensor connector, or the sensor can be knocked off its pipe during washing. Drying and refitting it is often enough.

What is the difference between J6 and H9?

J6 is the sensor clipped to the condenser coil pipe, while H9 is the sensor that reads the ambient air around the outdoor unit.

This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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