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Error code reference

Samsung Air Conditioner Error Code E242

Equal oil temperature sensor error (open/short).

Samsung codesSamsung air conditioner codes

Equal oil temperature sensor error (open/short).

First step from the service manual

Check if the outdoor oil temperature sensor connector is separated from PCB.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E242 means on a Samsung air conditioner

The E242 error code on a Samsung air conditioner indicates a fault with the equal oil temperature sensor located in the outdoor unit. This sensor monitors the temperature of the refrigerant oil in the compressor system, which is critical for maintaining proper lubrication and preventing compressor damage during operation. The error is triggered when the system's PCB detects either an open circuit or a short circuit condition in the sensor circuit, meaning the resistance reading falls outside the acceptable range expected for normal operation.

An open circuit condition occurs when electrical continuity is broken somewhere in the sensor circuit, causing the PCB to read an abnormally high resistance value or no signal at all. A short circuit condition is the opposite: resistance drops abnormally low, indicating the sensor leads or wiring are contacting each other or a grounded surface. Both conditions prevent the control board from receiving accurate oil temperature data, which triggers the fault code as a protective measure to avoid compressor damage.

The most common starting point for diagnosis is inspecting the outdoor oil temperature sensor connector at the PCB. A disconnected, corroded, or improperly seated connector can mimic both open and short circuit faults. If the connector is secure, the sensor itself should be tested for resistance values consistent with its rated specifications. Damaged wiring harnesses, moisture intrusion into connectors, and a failed sensor thermistor are the next most likely culprits.

Source: manufacturer service documentation.

Common causes of E242

  1. 01

    Disconnected sensor connector at PCB

    Wiring / connection

    The outdoor oil temperature sensor connector may have come loose or separated from the control board. This is the first thing to inspect, as a disconnected connector directly causes an open circuit reading and triggers E242.

  2. 02

    Failed oil temperature sensor thermistor

    Part replacement

    The thermistor inside the sensor may have failed, causing it to produce an out-of-range resistance reading consistent with either an open or short condition. The sensor should be tested with a multimeter and replaced if resistance values are incorrect.

  3. 03

    Damaged or broken sensor wiring harness

    Part replacement

    The wiring between the oil temperature sensor and the PCB may be pinched, cut, or corroded, creating an open or short circuit. Visually inspect the harness for wear, rodent damage, or chafing against metal components.

  4. 04

    Moisture or corrosion in the connector

    Wiring / connection

    Water intrusion into the sensor connector can cause corrosion on the terminals, leading to high resistance or intermittent contact. Inspect the connector for green or white oxidation on the pins and clean or replace as needed.

  5. 05

    Faulty outdoor PCB

    Part replacement

    If the sensor, connector, and wiring all test correctly, the outdoor control board itself may have a defect preventing it from reading the sensor signal accurately. PCB replacement is typically a last resort after all other causes are ruled out.

See the test procedure for each cause

Frequently asked questions about E242

What does E242 mean on a Samsung air conditioner?
E242 indicates an open or short circuit fault in the equal oil temperature sensor circuit in the outdoor unit. This sensor monitors compressor oil temperature to protect the system during operation. The error means the control board is receiving a signal that falls outside the expected range, either no signal at all or an abnormally low resistance reading. The system flags this fault to prevent potential compressor damage from running without accurate oil temperature data.
Can I fix the E242 error myself?
Some basic checks are accessible to a knowledgeable DIYer, such as verifying the sensor connector is securely seated on the outdoor PCB. However, testing sensor resistance, inspecting wiring harnesses, and replacing components inside the outdoor unit typically require familiarity with HVAC electrical systems and refrigerant safety. If you are not comfortable working inside the outdoor unit, a qualified technician should perform the diagnosis and repair.
Is it safe to run my air conditioner with error code E242 active?
It is not recommended to continue operating the unit while E242 is active. The oil temperature sensor is a protective component, and running the system without accurate oil temperature monitoring could result in compressor overheating or damage. You should address the fault before resuming normal operation to avoid more costly repairs.
How much does it cost to repair a Samsung air conditioner showing E242?
Repair costs vary depending on the root cause. If only the connector needs to be reseated, there may be no parts cost, just a diagnostic service fee. Replacing the oil temperature sensor typically costs between $50 and $150 for the part, plus labor. If the outdoor PCB needs replacement, total costs can range from $300 to $700 or more depending on the model and technician rates.
Will resetting my Samsung air conditioner clear the E242 error?
A power reset may temporarily clear the error display, but if the underlying fault in the sensor circuit is still present, E242 will return once the system runs a diagnostic cycle again. Resetting without addressing the cause does not fix the problem. A proper repair of the sensor, wiring, or connector is required to permanently clear the code.

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