Bosch dishwasher model SHE4AM16UC/01 installed in May 2009. Recently, performance has been poor: top rack not cleaned well, liquid soap not removed fully from dispenser, etc.

Using GoPro video, I've determined that the upper arm is not moving, lower arm sluggish. Replaced the circulation pump/heater, without any improvement.

Ran further tests by adding water following initial fill stage, better pressure to arm, but still not great (upper arm tries to turn, lower arm turns faster).

Measured initial water fill at start of cycle to be about 16 seconds. That seems too low to me given the diameter of the water valve outlet (I haven't yet measured volume of water flowing during the 16 second cycle, but it can't be more than about 1.5 l).

Thinking now a faulty power module, though the system doesn't show any fault codes. --g

  • 2
    Could have a blockage or build up of dirt. Do the arms spin easy by hand and/or they motor driven?
    – crip659
    Apr 2, 2022 at 16:21
  • If it's not filling very fast, water pressure might be low (blockage is a possibility, especially considering you've already replaced the pump) and then the arms won't spin very fast either. Kudos for going inside the machine with a GoPro btw :)
    – MiG
    Apr 2, 2022 at 18:19
  • add some CLR to a filled basin halfway through the cycle to remove lime/scale from the tubes and nozzles.
    – dandavis
    Apr 2, 2022 at 21:41
  • If it is not filling check the inlet for a screen that may be plugged , even if we all have the same model our fill times would possibly way different due to pressures ranging from 40 to 80 on average but I would agree 13 seconds is two short to get much water, it should have a level sensor and that is most likely faulty, not enough water to pump the spray arm can’t spin
    – Ed Beal
    Apr 3, 2022 at 2:19
  • Thanks for your responses, but not answering my question re initial programmed water fill time. This Bosch model opens the water fill valve based on a programmed time, which appears to be about 16 sec. Assuming flow similar to our kitchen faucet, which uses the same diameter supply hose, volume should be about 1.5 l initially. Seems low to me, regardless of inlet valve condition. --g
    – DrGER
    Apr 3, 2022 at 17:52

1 Answer 1


After a bit more investigation, including inlet valve replacement, we determined the poor performance was due to the hot water supply hose, which was nearly plugged at the supply valve fitting end:

enter image description here

This after almost 13 years of operation. Knock on wood we won't need to muck with this again for a while. --g

  • Out of curiosity, what is that? If it's calcium buildup, might be worth decalcifying the water before it enters your devices (dishwasher, laundry machine etc).
    – MiG
    Apr 28, 2022 at 9:55

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