CH65

Heat Sink Temperature Sensor Error

Home Appliance Error Codes LG Split AC

Can you still use it? With care until repaired

Who can fix it? Needs an authorized technician

Typical repair time 30 minutes – 3 hours

Typical cost SAR 100 to 2,500

What it means

This code appears on LG inverter split air conditioners and on LG ducted and cassette units that use CH codes. It means the heat sink temperature sensor that watches the IPM on the outdoor inverter board is giving an impossible reading because of an open or short circuit. On many models this sensor is built into the IPM or the board itself. The unit stops the compressor because it cannot protect the board without this reading. The wording can differ between series, and the same code can mean something else on other brands.

Models covered: LG inverter split air conditioners (e.g. Dual Inverter) and LG ducted/cassette units that use CH codes; the code shows as CH plus a number on the display or as LED blinks.

Symptoms3

CH65 shows and the compressor does not run.
The code may appear right at start-up even when the unit is cold.
The indoor fan runs but there is no cooling.

Possible causes4

Failed sensor built into the IPM or outdoor PCB.
Loose or corroded sensor connector on models where the sensor is separate.
Moisture, dirt or insects inside the outdoor board box.
Damaged tracks on the outdoor PCB from heat or moisture.

How to diagnose5

Switch off the breaker for several minutes, then restart.
After discharge, a technician inspects the outdoor board box for moisture, insects or burn marks.
Check the LG manual for the model to see whether the sensor is separate or built into the board.
If separate, measure its resistance against the LG table and check its connector.
If built in and no outside cause is found, the usual fix is a new outdoor PCB.

How to fix4

Clean and dry the board box and seal insect entry points.
Secure the sensor connector or replace a separate sensor.
Replace the outdoor PCB if the sensor is built into it.
Run the unit and confirm the compressor starts and 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.

The cost is low if the sensor is separate or the issue is moisture; where the sensor is built in, the usual fix is a new outdoor PCB.

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

Does CH65 always need a new board?

Not always. If the sensor is separate or the cause is moisture in the board box, the fix is simple; if it is built into the board, replacement is the usual fix.

What is the difference between CH62 and CH65?

CH62 means the sensor is reading a genuinely high temperature. CH65 means the sensor itself has failed and gives an impossible reading.

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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