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Error code reference

Haier Heat Pump Error Code 2 flashes

Compressor discharging temperature sensor failure.

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Compressor discharging temperature sensor failure.

First step from the service manual

Check the discharging temp sensor connection at CN7; sensor failure alarm triggers 30 seconds after disconnect detected. Failure is resumable.

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What 2 flashes means on a Haier heat pump

The 2-flash error code on a Haier heat pump indicates a compressor discharge temperature sensor failure. This sensor monitors the temperature of the refrigerant as it exits the compressor at high pressure and high temperature. Accurate discharge temperature readings are critical for protecting the compressor from overheating and ensuring efficient refrigerant cycle operation. When the control board loses a valid signal from this sensor, it triggers the fault condition.

The system is designed to detect a disconnect or out-of-range signal from the discharge temperature sensor connected at the CN7 port on the control board. The alarm does not trigger immediately upon signal loss. Instead, the board waits 30 seconds after detecting the abnormal condition before registering the fault. This delay helps prevent nuisance faults caused by momentary signal interruptions.

This fault is classified as resumable, meaning the system can recover and return to normal operation once the sensor fault is resolved. The most likely causes include a loose or corroded connector at CN7, a damaged sensor wire harness, or a failed sensor itself. Before replacing the sensor, inspecting the CN7 connection for proper seating, corrosion, and pin damage is the recommended first step. If the connection is secure and undamaged, resistance testing of the sensor against its specified values will confirm whether the sensor element itself has failed.

Source: manufacturer service documentation.

Common causes of 2 flashes

  1. 01

    Loose or disconnected connector at CN7

    Wiring / connection

    The discharge temperature sensor plugs into the CN7 port on the control board. Vibration or improper servicing can cause this connector to work loose, interrupting the signal. Reseating the connector firmly is the first diagnostic step.

  2. 02

    Corroded or damaged CN7 connector pins

    Wiring / connection

    Moisture intrusion or age can cause corrosion on the CN7 connector pins, leading to high resistance or no continuity in the sensor circuit. Inspect the pins visually and check for oxidation or bent contacts.

  3. 03

    Damaged sensor wiring harness

    Part replacement

    The wire running from the compressor discharge sensor to the CN7 port can become pinched, chafed, or broken, especially near sharp sheet metal edges or areas exposed to heat. A visual inspection and continuity test of the harness will identify breaks.

  4. 04

    Failed discharge temperature sensor

    Part replacement

    The sensor element itself can fail due to heat exposure, age, or manufacturing defects, producing a signal that is out of range or completely absent. Resistance testing of the sensor and comparing readings to specified values will confirm sensor failure.

  5. 05

    Faulty control board CN7 port

    Part replacement

    In rare cases, the CN7 port or the associated input circuit on the control board may be damaged, causing the board to misread or fail to detect a functioning sensor. This is typically diagnosed only after the sensor and wiring have been confirmed good.

See the test procedure for each cause

Frequently asked questions about 2 flashes

What does 2 flashes mean on a Haier heat pump?
Two flashes on a Haier heat pump indicate a compressor discharge temperature sensor failure. The control board has detected that the sensor connected at the CN7 port is sending an invalid or absent signal. The fault triggers 30 seconds after the signal loss is detected, and the system will not operate normally until the sensor issue is resolved.
Can I fix the 2-flash error on my Haier heat pump myself?
If you are comfortable working with electrical connectors, you can start by checking whether the sensor connector at CN7 on the control board is fully seated and free of corrosion. Reseating a loose connector may resolve the fault without any parts needed. However, if the sensor or wiring harness needs replacement, or if the control board is suspect, a qualified technician should handle the repair.
Is it safe to run my Haier heat pump while the 2-flash error is active?
The 2-flash fault is designed to prevent the compressor from running without valid discharge temperature monitoring, which protects the compressor from undetected overheating. You should not attempt to bypass this fault and run the system, as doing so could risk compressor damage. Address the sensor issue before returning the unit to service.
Will resetting my Haier heat pump clear the 2-flash error code?
Because this fault is classified as resumable, the system can recover once the underlying sensor issue is corrected. A power reset may temporarily clear the fault code, but the error will return within 30 seconds if the sensor or its wiring connection at CN7 remains faulty. A reset is not a fix and should only be used after the sensor connection has been inspected and corrected.
How much does it cost to repair the 2-flash compressor sensor error on a Haier heat pump?
Repair costs depend on what is causing the fault. If only the CN7 connector needs reseating, the cost may be limited to a service call fee, typically in the range of $75 to $150. If the discharge temperature sensor itself needs replacement, parts and labor combined generally range from $100 to $300 depending on your location and technician rates. Control board replacement, if required, would be a higher-cost repair.

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