Meiko Commercial Dishwasher Messages 500-505: Energy Optimization
Messages 500 to 505 on a Meiko M-iClean U relate to energy optimization. Message 500 means the mode is active and needs no action. For 501 to 505, keep working, and call us if the same number repeats.
Low: informational or a missed target; the unit keeps washing.
- Code
- 500 - 505
- Maker
- MEIKO
- Equipment
- Dish machines
- Applies to
- M-iClean U (red/gray messages)
What does MEIKO error code 500 - 505 mean?
The M-iClean U has an energy optimization mode that trims the work the machine does to save power and water. Message 500 simply tells staff the mode is active, and the manual says it needs no action. Messages 501 to 505 are different. They report that, while the mode was running, the tank temperature, the final rinse temperature or the wash time was not reached. In other words, the machine tried to hold to its savings targets and fell short of what the wash program needed. Staff only need to act when a number repeats. A single appearance can follow a cold start, a busy stretch or a door left open, and it passes by itself. Repeated appearances of the same number point to heating that is running below capacity, a sensor reading off, or a supply issue such as the water not reaching the machine. The maker's instruction is to call a service technician if they repeat.
Affected models and control systems
This applies to Meiko M-iClean U undercounter dishwashers with the energy optimization mode in the red and gray message list. Other Meiko ranges use different numbers.
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
- Message 500 shown during normal use
- Message 501 to 505 appearing now and then
- Dishes slightly less hot or dry after a busy period
Possible causes
Listed in MEIKO's documentation
- Tank temperature not reached under energy optimization
- Final rinse temperature not reached
- Wash time not reached
- Heating parts or sensors that run below capacity
Other likely causes — what usually sits behind error code 500 - 505 on this control. A technician confirms which one it is before any part is replaced.
- Cold incoming water on a morning start that slows tank heat-up
- Door opened repeatedly during the cycle, which cools the chamber
- A temperature sensor that reads low and holds the heat-up back
Safe checks before calling for service
- If you see 500, do nothing. It is information only.
- For 501 to 505, note the number and keep working.
- Check that the door is shut fully and the water supply is open.
- Write down the time of day and how many loads came before.
- Call us if the same number repeats, as the owner's manual says.
How a technician diagnoses error code 500 - 505
- Read the active message and its recent history.
- Check incoming water supply and temperature.
- Measure tank and final rinse temperatures against the program targets.
- Test the heating elements and their contactors with a meter.
- Check the temperature sensors for correct readings.
- Replace the element or sensor only after the test.
- Testing heating elements means live 208-240 V wiring behind the panels.
- Comparing real temperatures to program targets takes calibrated probes and the machine's own settings.
- A sensor that reads wrong can look just like a weak element, and telling them apart needs a meter.
How error code 500 - 505 differs from similar codes
Message 500 is a status note while 501 to 505 report a target missed; the energy mode itself is what separates this group from the heating errors.
Technical reference
- Document
- M-iClean U Original operating instructions 9763258 (update 2026-06), 9.4.1 Messages p.43-45
- Edition
- 9763258 / Valid from: 2018-09 / Update: 2026-06
- Models / control
- M-iClean U (red/gray messages)
- Section
- 9.4.1 Messages, printed pp. 43-45 of 70 (PDF pp. 43-45)
- 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 MEIKO dish machine error codes
Is 500 a problem?
No. It tells you energy optimization is active and needs no action.
Can I keep washing with 501?
Yes, but note it. A one-time message can pass by itself.
What if 503 keeps coming back?
A repeating number points to heating or a sensor. Call us.
Need help with MEIKO error code 500 - 505?
A technician confirms the cause on site and gives you the price in writing before any work starts.