Halfway through cycle, red LED flashes "Check drain".

LED L1+ L2/Fault code F7, Pumping out fault (machines with
pressure sensor)
Water not evacuated after 120 seconds pumping out. Program
interrupted.
Check: Drain pump, hoses, installation of drain hose, control unit and wiring.

Dado

http://m.miele.ca/OperatingInstructions/en-CA/Dishwashers/Previous%20models/Miele%20Dishwasher%20Manual%20G851%20SC%20Plus.pdf
Page 39

replace the motors brushes check the filters
and clear any bits of bra wire etc

then reset the machine {usually hold power in and apply the mains}

F21 F 22 CCU /touchpad/LED assembly unable to transmit/receive data to/from the CCU central control unit
Possible causes/proceedure:
1. Check the touch-pad/LED assembly by selecting different
cycles and changing the modifiers and options available to
confirm the touch-pad/LED is responding.
2. Unplug washer or disconnect power.
3. Check wire harness connections to the
touch-pad/LED assembly and Central Control Unit (CCU).


Sud: Suds lock (overdose of detergent detected during wash cycle)
The motor control unit senses a suds lock condition by analyzing the
current draw on the drive motor. If "Sud" is displayed a potential Suds
Lock is detected. This may signify a bad pump, an extra heavy load,
excessive detergent, or excessive suds.
Possible causes/proceedure:
¦ If too much detergent was used:
-Run the unit through a Rinse/Spin cycle.
-Run a Normal cycle without adding any detergent.
This should clear the unit of the excess detergent.
1. Check the drain hose and make sure it is not plugged
or kinked.
2. Unplug washer or disconnect power.
3. Check wire harness connections to the drain pump,
pressure switch, and Central Control Unit (CCU).
4. Check/clean drain pump filter of foreign objects.
5. Plug in washer or reconnect power.
6. Check drain pump.
7. Check the pressure switch.
8. Verify CCU operation by running a Diagnostic test or any
cycle.

First remove the bottom panel and grab yer tech sheet. It gives the faluts and directions to diagnose or correct as shown above. Clear the pump filter.
Watch this video that shows how from my main man Double H

If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61

There are several possibilities, the drain valve is opening and closing, this causes water to fill the base, the float valve will not achieve the desired level so the fan will not start. This could be the drain valve actuator is U/S or the PC board. Have you tried to turn the main power off at the switch board for 1/2 hour?
Most occasions the service person will swap out all the units as they purchase it as a package. It is not cheap to replace these units.

Frigidaire, Zanussi, AEG, & More....

EFO = Filter Blocked (low flow) and it is accessible from the bottom front of the machine.

1. there is a blockage in the filter or drain hose.takes too long to drain out.
2. over dosing of powder or liquid. again can cause an air lock in the pump which slows the drain pump down.

Check the filter and drain hose and test again. this fault will only come up at the end of a cycle.
You do not need to reset the machine to get rid of the fault code as this is automatically deleted.

Run an empty load with no detergent in an attempt to get rid of the code.

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red light is check drain?
Clogged by something.
Could be a coin.
Use to have large coin when i was young and forgot remove from my jeans. So mum made me repair that every time. In that case filter clean, but coin bloking filter inlet.
Not necesarily coin in your case.
never buy these deals over Ebay my advice.
If you have the machine already then this is first to look for.

MOST LIKELY problem is the convergence amps but.....
It might be your vertical or horizontal circuit...those initiate a 3 blink failure code too....

You will more that likely have a faulty waterproof inlet system