Dishwasher Whirlpool adp4601 four flashes

[drewid]

Which is apparently drainage...except it seems to drain fine.
Diagnostic turn-off,hold-start-button,turn-on,press-button-when-flashes comes up with four flashes.

Stuff I've tried so far:
bowl of water in the bottom drains fine.
Kettle full of boiling water in the sump, drained fine.
Took out the sump pressure switch, cleaned and tested. Outer pins connect/disconnect when membrane is pressed, so I guess that's ok?

How do I identify/test the OWI thing or water indicator?

 

[zipper]

Post the 12NC number on the door sticker (12 digits & starts with 85---).

 

[drewid]

The number is: 8511 505 15810

Thanks.

 

[zipper]

There is no OWI on your model...only a WI (the black pressure switch in the RH side of the sump). The pressure switch often gets clogged, but if you are sure this functions correctly then you need to look elsewhere. Check the sink spigot & drain hose are clear. Disconnect & drain the machine then lie it on its back. There is a removable base-plate, take it off & make sure it isn't deformed causing the antiflood switch to engage. Remove the drain pump & check for pieces of glass or similar. Turn the motor impellor, it should exhibit noticeable magnetic resistance before flicking over & there should be no sideways play on the drive-end bearing. If you find either replace the pump. There is a non-return flap in the pump drain exit, make sure it isn't jammed.

 

[drewid]

OK, so in and out pipes are clear and flowing fine, the pump rotor does the resistance then flick thing.

Couldn't find a non-return flap, is that in the outflow pipe itself?

I tried a diagnostic run again, it got all the way through the cycle, with water flowing in and heating correctly and draining at the end, but still comes up with the four flashes in spite of having actually drained properly.

I'm wondering if the connector to the pressure switch might be the problem?
It doesn't seem particularly tight.

 

[zipper]

You could always try to give the connector a nip to make it tighter but I doubt very much if that is your problem. If the dishwasher is a few years old the pressure switch diaphragm may be distorted. It may seem to switch ok when you poke something through the grill but still malfunction under water pressure. Or the pump could be on the way out. If it seems to drain properly I think I would tend to suspect the pressure switch.

 

[drewid]

OK. That's odd.
We just put it through another diagnostic cycle (actually to get the lunch things washed up ) and it came through showing no errors.

It's not the first time it's shown four flashes, but it's the first time that cleaning the switch hasn't fixed it, so I think it's quite likely to happen again.

I'm guessing the pressure switch won't be that expensive, so I'll order one anyhow and swap it out when it happens again.

Thanks a load for your help, it's been very much appreciated.

 

[zipper]

http://www.espares.co.uk/parts?k=481227128407
You may find it cheaper shopping around.