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Error code reference

LG Microwave Error Code E-83

PCB communication error between main PCB and sub PCB.

LG codesLG microwave codes

PCB communication error between main PCB and sub PCB.

First step from the service manual

Check main harness and display connector.

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 E-83 means on a LG microwave

The E-83 error code on an LG microwave indicates a communication failure between the main PCB (primary control board) and the sub PCB (typically the display or secondary control board). These two boards continuously exchange data signals to coordinate functions such as display output, keypad input, power control, and timing. When that communication link is interrupted or returns unexpected signals, the main PCB flags the E-83 fault and halts normal operation to prevent erratic behavior.

The most common point of failure in this communication circuit is the wiring harness connecting the two boards, along with the connectors at each end. Loose, corroded, or damaged connector pins can cause intermittent or complete signal loss. The display connector is particularly vulnerable because it is physically handled during servicing and can experience stress from door vibration over time. A thorough inspection of the main harness and display connector is always the correct starting point before condemning either board.

If the harness and connectors check out visually and electrically, the fault may lie within the sub PCB itself or, less commonly, the main PCB. A failed communication driver component on either board can prevent the data exchange from completing properly. Because both boards must function together for the appliance to operate, diagnosing which board is at fault typically requires substitution testing or detailed circuit-level measurement of the communication lines between the two boards.

Source: manufacturer service documentation.

Common causes of E-83

  1. 01

    Loose or disconnected harness connector

    Wiring / connection

    The wiring harness connecting the main PCB to the sub PCB may have a connector that has worked loose over time due to vibration. Inspect both ends of the main harness for connectors that are not fully seated.

  2. 02

    Damaged or corroded connector pins

    Wiring / connection

    Pins inside the display connector or main harness connector can corrode or become bent, preventing reliable signal transfer. Look for discoloration, oxidation, or physically deformed pins at each connection point.

  3. 03

    Broken or shorted wiring in the main harness

    Part replacement

    The harness wires themselves can develop breaks or shorts, particularly near stress points where the cable bends. Carefully flex the harness while inspecting for damaged insulation or broken conductors.

  4. 04

    Failed sub PCB

    Part replacement

    If the harness and connectors are intact and undamaged, the sub PCB may have an internal component failure that is preventing it from communicating with the main board. Substitution testing is typically needed to confirm this.

  5. 05

    Failed main PCB

    Part replacement

    In less common cases, the main PCB itself loses the ability to send or receive communication signals due to a failed component on its communication circuit. This is usually diagnosed only after ruling out the harness, connectors, and sub PCB.

See the test procedure for each cause

Frequently asked questions about E-83

What does E-83 mean on a LG microwave?
E-83 indicates a PCB communication error between the main control board and the sub PCB in your LG microwave. The two boards have lost the ability to exchange data signals, which causes the unit to stop operating. This fault is most often traced to the wiring harness or connectors linking the two boards, though the boards themselves can also be at fault.
Can I fix the E-83 error myself?
A knowledgeable DIYer can start by unplugging the microwave and carefully inspecting the main harness and display connector for loose, corroded, or damaged connections. Reseating connectors firmly may resolve the error if a loose connection is the cause. However, if the harness or a control board needs replacement, working inside a microwave carries high-voltage risks even when unplugged due to the capacitor, so professional service is strongly recommended.
Is it safe to use my LG microwave when it shows E-83?
No, you should not attempt to use the microwave while E-83 is active. The error means the control boards cannot communicate properly, and the unit will not operate normally in this state. Attempting to force operation could lead to unpredictable behavior. Unplug the appliance and have it inspected before use.
Will resetting the microwave clear the E-83 error?
Unplugging the microwave for a minute and restoring power may temporarily clear the code if the communication failure was caused by a transient glitch. However, if the underlying cause is a loose connector, damaged harness, or faulty board, the E-83 error will return. A reset alone is not a fix and the wiring should still be inspected.
How much does it cost to repair an E-83 error on an LG microwave?
Repair costs depend on the root cause. If only a harness connector needs reseating or a damaged harness needs replacement, costs are generally lower, typically in the range of $50 to $150 for parts and labor. If the sub PCB or main PCB requires replacement, parts alone can range from $80 to $250 or more depending on the model, with additional labor costs on top. In some cases, replacement of the appliance may be more economical than board-level repairs.

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