Bosch dishwasher won't drain

Dishwasher Repair
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1

I came home to find two things

  1. Burned electrical smell in the house
  2. Dishwasher had failed to drain

I cannot tell for sure if the two are connected, but it seems likely.

The filters were not clogged, and the drain impeller does not appear to be clogged. I find the impeller does not spin freely - it resists then moves in jerks. Kind of like turning a piston-driven shaft if you know what I mean.

I tried using the posted online manual to ohm-out the drain motor from the front panel, but the schematic for the SHU 33 does not appear to match mine (SHU33A06/22).

Suggestions?

3

After three cycles with no problem, it’s back to leaving the tub full of water. Seems to run through normally, but the tub is full of water at the end.

4

Still no solution.
Symptoms:

  • Burned electrical smell during cycle
  • Tub is full of water at the end

What I’ve done:
Verified drain lines are clear
Verified drain hose has proper loop
Removed and inspected the circuit board - looks okay.
Replaced the drain pump.

  • Old pump appears to be fine, after removal
  • It ran two cycles normally after replacing the pump, then back to the
    same failure mode.

Any troubleshooting suggestions?