Speed Queen Washer Error Code E Co: SCI Communication Error
E Co is an SCI communication error, meaning the front control and the output board cannot talk to each other on Quantum topload washers and CHM1792C washer-extractors. Power the machine down and up as the manual says, and call us if it returns.
High: the two boards cannot communicate and the machine will not run.
- Code
- E Co
- Maker
- Speed Queen
- Equipment
- Washers
- Applies to
- Quantum topload (TLW13C family) electronic control; CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
What does Speed Queen error code E Co mean?
Two boards share the work in these machines. The front control takes your selections and decides what should happen, while the output board, also called the input and output board, operates the valves, the lock and the drive. They exchange messages over an SCI link, a serial communication line. When the front control stops getting valid replies from the output board, it cannot know whether commands are being carried out, and it stops the machine and shows E Co (display text: E Co). The code is about the conversation between the boards. It is not a water, door or motor report. The manual lists the cable between the boards, power to each board, connectors for corrosion or looseness, and either board itself. On the CHM1792C, the owner's manual says to disconnect and reconnect power. If the link recovers after that, a brief supply dip may have confused it. If E Co comes back, the cable, a connector or a board is the likely cause.
Affected models and control systems
Speed Queen Quantum topload washers (TLW13C family) and CHM1792C family washer-extractors (QN models, 20-100 lb) with the front-end control. E d Co is the drive-board version on washer-extractors.
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
- E Co on the display
- The machine stops or will not start
- Buttons seem to work but nothing happens in the cycle
Possible causes
Listed in Speed Queen's documentation
- Cable between control and output board
- No power at one of the boards
- Connectors corroded or loose
- Either board failed
Other likely causes — what usually sits behind error code E Co on this control. A technician confirms which one it is before any part is replaced.
- A cable pinched where the control panel hinges or lifts
- Water vapor corroding the connector pins over time
Safe checks before calling for service
- On the CHM1792C, disconnect and reconnect power, as the owner's manual says.
- Give the lock time to let go before the door or lid is opened.
- Leave the cabinet closed.
- If E Co returns, contact us to book a visit and tell us how soon after power-up it appeared.
How a technician diagnoses error code E Co
- Read E Co and note whether it appears at power-up or mid-cycle.
- Check supply voltage to both boards.
- Inspect the communication cable for damage and the connectors for corrosion.
- Reseat or clean the connections with power off.
- Swap or replace a board only after the cable and supply are proven good.
- Both boards and their cable are inside the cabinet near live 208-240 V.
- Telling a bad cable from a bad board requires known good parts or a meter on the link.
- Board replacement involves restoring the machine's own programming.
How error code E Co differs from similar codes
E d Co is the washer-extractor's drive-board communication error; E Co concerns the output board.
Technical reference
- Document
- Commercial Troubleshooting Topload Washers TLW13C, Part No. 203502R4, March 2024, Error Code Listing (pp. 30-32)
- Edition
- Part No. 203502R4, March 2024
- Models / control
- Quantum topload (TLW13C family) electronic control; CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
- Section
- Section 3 General Troubleshooting - 20. Error Code Listing, printed pp. 30-32 (PDF pp. 32-34)
- 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 Speed Queen washer error codes
Is E Co the same as E d Co?
No. E Co is the output board link; E d Co is the drive board link on washer-extractors.
Can I run the machine after a restart?
Only if it works; if E Co returns, stop and call.
Is it a software problem?
It can be, but cables and connectors are the more common reasons.
Need help with Speed Queen error code E Co?
A technician confirms the cause on site and gives you the price in writing before any work starts.