UniMac Washer Error Code Eio 36: Door Lock Pulse Hardware
Eio 36 on a UniMac QN washer-extractor means the door lock solenoid pulse hardware failed its check on the I/O board. It is the hardware side of Eio 31, and the board may not be able to engage the lock. Note what the door did, switch off, let the drum stop, and call us.
High: the lock may not engage, so the cycle stops and the machine should stay off.
What does UniMac error code Eio 36 mean?
Eio 36 on UniMac QN washer-extractors such as the UCA020QN means the door lock solenoid pulse hardware failed its check on the input and output board. It is the hardware side of Eio 31. The pulse circuit is the part of the board that sends the short burst of power that moves the lock into place. When the board tests this circuit and it fails, it cannot be trusted to engage the lock, and a washer must not run a cycle without a proven lock. The control stops the cycle and holds the code. The board is reporting on itself, and the door panel may be perfectly fine. The manual lists a failed pulse circuit on the I/O board for the lock solenoid, a lock solenoid or harness shorted and loading the pulse output, and a connector at the I/O board that is not seated firmly.
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 36 on the display and the cycle stops
- Door lock does not make its usual sound
- Door may feel unlatched
- Code remains after a restart
Possible causes
Listed in UniMac's documentation
- Failed pulse circuit on the I/O board for the lock solenoid
- Lock solenoid or harness shorted, loading the pulse output
- Connector at the I/O board not seated firmly
Other likely causes — what usually sits behind error code Eio 36 on this control. A technician confirms which one it is before any part is replaced.
- A harness shorted to the door frame where insulation has rubbed through
- A board connector worked loose when the front panel was last removed
- Pulse circuit parts aged by many thousands of lock cycles in a busy laundry
Safe checks before calling for service
- Make a note of Eio 36 and what happened with the door.
- Switch off the machine and let the drum stop.
- Do not reach into the drum area.
- Call us so we can test the pulse circuit.
- Tell us whether the door felt latched before the stop.
How a technician diagnoses error code Eio 36
- Read the code and ask how the door behaved.
- With power locked out, inspect the connector at the board and the lock harness for rubbing and shorts.
- Measure the solenoid resistance and insulation to ground.
- Check the pulse output at the board while a lock command is given.
- Replace the harness, solenoid or board, whichever fails the test.
- The pulse is driven from the board's output stage at machine voltage, so testing is done on an energized circuit.
- Reaching into the drum area on a machine whose lock is in doubt is dangerous.
- A harness short and a failed pulse driver give the same code and need measuring to separate.
How error code Eio 36 differs from similar codes
Eio 36 is the hardware check behind Eio 31. Eio 37 is the complete lock output test.
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
How does Eio 36 relate to Eio 31?
Eio 31 is the pulse pin; Eio 36 is the pulse hardware that sits behind it.
Can I hold the door shut and run?
No. The lock must be proven before any cycle.
Will a restart help?
It may clear the display, but the board will fail its check again if the pulse circuit has failed.
Need help with UniMac error code Eio 36?
A technician confirms the cause on site and gives you the price in writing before any work starts.