UniMac Washer Error Code Eio 38: Mosfet Enable Will Not Turn On
Eio 38 on a UniMac QN washer-extractor means the Mosfet enable on the I/O board cannot be enabled: the control asked the board to switch on its outputs and nothing turned on. Valves, the lock and other outputs cannot be powered, so the cycle stops. Switch off, look for water on the floor, and call us.
High: nothing on the board can be switched on, so no cycle can run.
What does UniMac error code Eio 38 mean?
On UniMac QN washer-extractors such as the UCA020QN, Eio 38 means the Mosfet enable on the input and output board cannot be enabled. The Mosfets are the electronic switches that power the board's outputs, and the enable line is the master permission for all of them. At the start of a cycle, the control asks the board to enable its outputs. If the enable does not turn on, the board has no way to power the water valves, the door lock and the other outputs. The control then stops the cycle and holds the code. Nothing will switch on until the problem is cleared. This differs from Eio 39, where the enable cannot be turned off. The manual lists the board supply and ground, the connectors to the board, moisture on the board, and the I/O board itself.
Affected models and control systems
Listed for the CHM1792C family of UniMac QN washer-extractors (20-100 lb), with the UCA020QN as the example model, on the input and output (I/O) board.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Eio 38 on the display and nothing switches on
- No water enters the machine and the door does not lock
- Same code on every attempt
- Damp area near the cabinet floor
Possible causes
Listed in UniMac's documentation
- Board supply and ground
- Connectors to the board
- Moisture on the board
- I/O board itself
Other likely causes — what usually sits behind error code Eio 38 on this control. A technician confirms which one it is before any part is replaced.
- A control-power connector with a loose pin that drops out when the cabinet vibrates
- Damp air in the cabinet from a poorly ventilated laundry room
- An enable driver that has aged and no longer switches on cleanly
Safe checks before calling for service
- Record Eio 38 and the point in the cycle.
- Switch the machine off at its power control.
- Look for water on the floor and dry it.
- Call us with the code.
- Keep the area dry and wait for us.
How a technician diagnoses error code Eio 38
- Read the code and check when in the sequence it appears.
- Measure the board's supply and ground with power on.
- Inspect connectors for looseness and corrosion with power locked out.
- Look for moisture and burn marks on the board and dry it if needed.
- Replace the I/O board if supply and connections are sound and the enable still will not turn on.
- Supply and ground measurements at the board are made with the cabinet open and control power present.
- Moisture on a board can hide under connectors and needs careful drying and inspection.
- Replacing a board needs the right part and a test cycle to confirm all outputs.
How error code Eio 38 differs from similar codes
Eio 38 is an enable that will not turn on. Eio 39 is an enable that will not turn off, which is more serious.
Technical reference
- Document
- Washer-Extractor Programming CHM1792C_SVG, Part No. F8641001ENR4, Error Codes Table 29 (pp. 100-107)
- Maker documentation
- UniMac owner support
- Edition
- Part No. F8641001ENR4, January 2020
- Models / control
- CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
- Section
- Error Codes, Table 29, pp. 100-108 (PDF pages equal printed pages)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related UniMac washer error codes
What is the difference between Eio 38 and Eio 39?
In Eio 38 the outputs cannot be switched on. In Eio 39 they cannot be switched off.
Will the machine do anything?
No. Without the enable, the valves and the lock cannot be powered.
Could moisture cause this?
Yes. The manual lists moisture on the board.
Need help with UniMac error code Eio 38?
A technician confirms the cause on site and gives you the price in writing before any work starts.