Samurai Appliance Repair Man's Blog

from the Bosch Service Manual:
DISHWASHER TEST PROGRAM ERROR CODES (on 2-digit digital displays):
0 – No faults
1 – Aqua Sensor (Sensotronic) fault
2 – Heating system fault (heater, Hi-Limit, flow switch, NTC, control module heater relay)
4 – Water filling fault
8 – NTC (temperature sensor) fault
16 – Water switch fault

Fault codes add up for multiple faults
(e.g. heating + water filling fault = 2 + 4 = 6)

I'm not a Bosch master, but it looks like 21 would be 16+4+1
Is there enough water in the Dishwasher ?

Source: Bosch SHX56B02UC Dishwasher

Replacing and re-programming the control in these Bosch dishwasher is a pretty  straightforward job.  But the instructions for the reprogramming are a little different from what you might actually see.  

Here's a video showing how to replace the control.  

And here are the written instructions from Bosch (click to enlarge):



In the video, the re-programming portion is the last 30 seconds or so of the video.  Notice that what they show in the video doesn't quite match up with what's shown in the video, in particular, the programming code shown in the display.  In the video, you see him cycle through a series of programming codes from 20 through 29 (this is how you'll usually see it in the field for models with the LED display) until he gets the code he wants, in his case, "21."  

In the written instructions, OTOH, they talk about programming codes of C0 through C4.  The discrepancy is that in the written instructions, they're using "C" to mean "code."  On the display, just ignore the first number ("2") and go by the the second number that changes as you cycle through it.  

So, for example, if your model number is SHU43C06UC, the target code is "1" and you cycle through until you see "21" in the display.

Use your model number to look up and buy the replacement control board here.  Comes with a full one-year, no-hassle warranty, even after it's already been installed!

Source: Bosch  D/W Model# shu43c06uc/17

Float Switch only controls the Water Valve

Field Service Test
A Field Service Test may be started by pressing the key 5 times followed by the key within 6 seconds.
This test must be performed with clean water to insure proper sensor performance.
“88” will appear in the display (if available*) and the following sequence of events will occur:

SECONDS . . . . . FUNCTIONS / ACTIVE LOADS
106 . . . . . . . . . . .Water Valve
5 . . . . . . . .. . . . .Thermistor check / Turbidity Sensor check & Calibration - no loads active.
120 . . . . . .. . . . . Wash Motor / Dispenser Wax Motor
180 . . . . . . . . . . .Wash Motor / Heater
120 . . . . . .. . . . . Drain Pump
4 . . . . . . . . . . . . .Water Valve
For manuals and lots of other goodies,
become an Apprentice==> http://appliantology.org/apprentice/

Source: Jenn-Air JDB1100AWS dishwasher - water left in basin after cycle