Alto-Shaam Combi Oven Error Code E103: Option Board Switch Setting
E103 Option Board Doesn't Send Switch Setting means the option board is not communicating with the control board. A technician should check the CAN cable, the control board dip switch, the software versions and the boards.
Medium: option board features are lost, and cooking may be affected.
- Code
- E103
- Maker
- Alto-Shaam
- Equipment
- Combi ovens
- Applies to
- Combitherm CT PROformance (CTP) and CT Classic (CTC)
What does Alto-Shaam error code E103 mean?
Some combi ovens carry an option board (OB) that adds features and talks to the control board (CB) over a CAN cable. At start-up the control board expects the option board to send its switch setting. If that does not arrive, the control posts E103 Option Board Doesn't Send Switch Setting. The manual lists five things to check: the CAN cable from OB to CB, the dip switch on the control board, which must be ON when an option board is fitted, software on the two boards that is not compatible, and then a failed option board or control board. The order matters. A cable and a dip switch cost little to check, while replacing boards is the last step. The message is a setup and communication problem, not a heating or water problem, so cooking functions may behave but the extra features do not. E104 describes the same condition.
Affected models and control systems
Alto-Shaam Combitherm CT PROformance and CT Classic combi ovens fitted with an option board, in sizes 6-10, 10-10, 7-20, 10-20, 20-10 and 20-20, electric and gas.
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
- E103 Option Board message on the display
- Option features missing from the control
- Message appearing at start-up
Possible causes
Listed in Alto-Shaam's documentation
- CAN cable between option board and control board
- Control board dip switch not set ON
- Incompatible option board and control board software
- Option board malfunction
- Control board malfunction
Other likely causes — what usually sits behind error code E103 on this control. A technician confirms which one it is before any part is replaced.
- A board replaced earlier with a different software version
- A CAN connector pushed loose when the panel was reassembled
Safe checks before calling for service
- Turn the oven off and on once and see whether E103 returns at start-up.
- Do not open the control panel.
- Note when the option board was last added or replaced.
- Give the technician the date of any software update.
How a technician diagnoses error code E103
- Read the code and ask about recent board work.
- Inspect the CAN cable from the option board to the control board.
- Check the dip switch on the control board is ON for an option board.
- Compare software versions on both boards and update if incompatible.
- Replace the option board or control board last.
- Dip switches and CAN connectors are on boards behind the panel.
- Software updates need the right files and tools.
- Replacing a board changes the oven's configuration.
How error code E103 differs from similar codes
E104 states the same condition as Option Board Not Communicating; E103 says the option board has not sent its switch setting.
Technical reference
- Maker documentation
- Alto-Shaam owner support
- Edition
- MN-35949 Rev 08 03/22
- Models / control
- Combitherm CT PROformance (CTP) and CT Classic (CTC)
- Section
- Error Codes, pp. 25-31
- 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 Alto-Shaam combi oven error codes
What is the option board?
An extra board that adds features and talks to the control board.
Is E103 the same as E104?
They describe the same lack of communication with different wording.
Does it affect cooking?
The manual does not say; it concerns the option board's link.
Need help with Alto-Shaam error code E103?
A technician confirms the cause on site and gives you the price in writing before any work starts.