# How to Fix Kenmore Error F28 (Serial Communication)
The F28 error is one of the most frustrating electronic issues because it often points directly to a major component failure. This guide will help you understand what this code means and provide actionable steps to diagnose the true source of the communication breakdown.
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## 1. Explanation: What is the F28 Error Code?
The F28 error code signifies a **Serial Communication Failure**.
In plain English, this means the main electronic control board (often called the CCU or Central Control Unit—the “brain” of the washer) is unable to communicate properly with one or more critical electronic components. This loss of communication prevents the washer from receiving or sending necessary signals to start or complete a cycle.
**The two primary components involved in an F28 error are:**
1. **The Main Control Board:** The master component that controls all functions.
2. **The Motor Control Board (MCU):** The component that regulates the speed and direction of the motor.
While a break in the wiring harness connecting these two components is possible, the most common culprit for F28 is a failure or malfunction within the **Main Control Board** itself.
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## 2. Step-by-Step Fix: How to Diagnose F28
Because this is a communication error, we must start with the simplest solution (a power reset) and move toward inspecting the wiring before confirming a component failure.
### Step 1: Execute a Hard Reset (Power Cycle)
Electrical errors can sometimes be temporary glitches caused by power fluctuations. A hard reset clears the fault memory.
1. **Unplug the Washer:** Completely disconnect the machine from the power outlet.
2. **Wait:** Leave the washer unplugged for a full **5 minutes**. This ensures any residual power drains from the circuit boards.
3. **Plug Back In:** Restore power and attempt to start a cycle.
If the F28 error reappears immediately, proceed to Step 2.
### Step 2: Inspect the Wiring Harness
The F28 error can occur if the serial communication cable connecting the main control board to the motor control board is loose, damaged, or corroded.
1. **Access the Control Boards:** Depending on your model (top-loader or front-loader), you may need to remove the top panel or rear panel to access the main control board and the motor control board (usually located near the bottom of the tub). *Always unplug the washer before opening the casing.*
2. **Locate the Harness:** Identify the multi-pin wiring harness that runs between the Main Control Board and the Motor Control Board.
3. **Check Connections:** Firmly push the connectors on both ends of the harness to ensure they are fully seated. Look for any wires that appear pinched, cut, frayed, or discolored.
4. **Inspect for Corrosion:** Water damage or high humidity can cause corrosion on the metal terminals, interfering with communication. Clean any mild corrosion with electrical contact cleaner or a pencil eraser.
If the connections are tight and the wiring looks perfectly intact, the communication failure is internal to one of the boards.
### Step 3: Inspect the Main Control Board for Visual Damage
Since the Main Control Board (CCU) is the typical point of failure for F28, a visual inspection can sometimes confirm the issue.
1. **Remove the Main Control Board:** Carefully unclip or unscrew the main control board from its housing (documenting or photographing the wiring connections first).
2. **Look for Burn Marks:** Inspect the surface and underside of the board. Look for any signs of heat damage, such as:
* Scorched or melted plastic.
* Dark, sooty spots around resistors or relays.
* A strong burnt electronic smell.
3. **Identify Component Failure:** If you see clear signs of burning, the board has suffered a power surge or component failure, confirming that a replacement is necessary.
If the wiring is good and the reset failed, regardless of visual confirmation, the Main Control Board has almost certainly lost its ability to manage serial communication and must be replaced.
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## 3. Call to Action
The F28 error is a complicated electrical issue that rarely resolves without replacing the defective component. Based on industry data for this error code, the Main Control Board is the likely culprit.
**Check the price for a replacement Main Control Board here: https://www.amazon.com/s?k=Kenmore+Main Control Board&tag=trivian-20**