mypros+
Error code reference

Samsung Air Conditioner Error Code E104

Communication error between Outdoor Main and Inverter Micom (occurred after 1 minute detection in Main and…

Samsung codesSamsung air conditioner codes

Communication error between Outdoor Main and Inverter Micom (occurred after 1 minute detection in Main and Inverter).

First step from the service manual

Check wiring between Main PCB and Inverter PCB.

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

MyPros+ Max

Get the full diagnostic procedure for E104.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What E104 means on a Samsung air conditioner

Samsung E104 is a communication fault that occurs when the outdoor unit's Main PCB loses its data link with the Inverter PCB (also referred to as the Inverter Micom board). These two boards work in constant communication to coordinate compressor speed, power delivery, and operational feedback. When the Main PCB cannot confirm a valid signal from the Inverter PCB for a continuous period of one minute, the system logs E104 and halts operation to prevent uncontrolled inverter behavior or compressor damage.

The most direct cause of this fault is a wiring problem between the two PCBs. Loose connectors, corroded terminals, pinched wiring harnesses, or broken conductors on the communication lines will interrupt the signal and trigger the one-minute detection timer. Voltage irregularities feeding the boards can also cause the communication protocol to fail, so power supply quality to the outdoor unit should be considered as a secondary factor.

Beyond wiring, an internally failed Main PCB or Inverter PCB can produce this code even when all wiring checks pass. If the harness integrity is confirmed and connections are secure, the fault points toward one of the two boards requiring testing or replacement. Technicians should also inspect for signs of moisture intrusion or pest damage inside the outdoor unit enclosure, as these are common causes of PCB communication failure in outdoor installations.

Source: manufacturer service documentation.

Common causes of E104

  1. 01

    Loose or disconnected wiring harness between Main PCB and Inverter PCB

    Wiring / connection

    The communication cable connecting the two boards may have worked loose due to vibration or was not fully seated. Inspect all connectors on both boards for a secure, click-locked fit.

  2. 02

    Corroded or damaged connector terminals

    Wiring / connection

    Outdoor unit exposure to humidity can cause terminal corrosion on the communication harness connectors, increasing resistance and breaking the signal. Look for green or white oxidation on the pins and clean or replace the affected connector.

  3. 03

    Broken or shorted communication wire

    Part replacement

    Physical damage to the wiring harness, such as pinching, rodent chewing, or insulation wear against a sharp edge, can open or short the communication circuit. Perform a continuity check along the full length of the harness.

  4. 04

    Failed Inverter PCB

    Part replacement

    If wiring checks out fully, the Inverter Micom board itself may have failed internally and is no longer responding to the Main PCB. Component-level testing or board replacement is required to confirm this.

  5. 05

    Failed Main PCB

    Part replacement

    Less commonly, the Main PCB is the source of the fault, either failing to transmit or failing to process a valid response from the Inverter PCB. This is typically diagnosed after the Inverter PCB and wiring have been ruled out.

See the test procedure for each cause

Frequently asked questions about E104

What does E104 mean on a Samsung air conditioner?
E104 indicates a communication error between the outdoor unit's Main PCB and its Inverter PCB. The system detected a loss of signal between these two boards for at least one minute before logging the fault and shutting down. The problem is located inside the outdoor unit and typically involves the wiring harness or one of the two control boards.
Can I fix E104 on my Samsung air conditioner myself?
A knowledgeable DIYer can safely inspect the outdoor unit's wiring harness for loose connectors or visible damage, which is the most common cause of this error. However, testing or replacing the Main PCB or Inverter PCB requires familiarity with electrical diagnostics and handling of high-voltage components inside the outdoor unit. If wiring inspection does not resolve the issue, a licensed technician should complete the repair.
Is it safe to keep running my air conditioner with an E104 error?
No. When E104 is active, the system has already shut down operation to protect the compressor and inverter components. Attempting to force the unit to run without resolving the communication fault could result in uncontrolled compressor behavior or further board damage. The unit should remain off until the underlying fault is diagnosed and corrected.
Will resetting my Samsung air conditioner clear the E104 error?
A power reset may temporarily clear the displayed code, but if the underlying wiring or board fault still exists, the error will return within a minute of the system attempting to restart. The one-minute detection window means the fault will reappear quickly if the root cause is not addressed. A reset is only useful for confirming whether the fault is intermittent or persistent.
How much does it cost to repair an E104 error on a Samsung air conditioner?
Repair costs vary depending on the root cause. If the issue is only a loose or corroded connector, a service call fee of roughly 75 to 150 dollars may be the primary expense. If a PCB replacement is needed, costs typically range from 200 to 600 dollars or more depending on the specific board and labor rates in your area. Getting a diagnostic visit before committing to parts replacement is advisable.

Related Samsung air conditioner codes

All Samsung air conditioner codes
View all 572 Samsung air conditioner codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass