Whirlpool WDF750SAYW intermittently won't start.

[mrfixiter]

This Whirlpool WDF750SAYW intermittently will not run for longer than a few seconds. After you select the wash mode and press start, things sound normal but then it sounds like the pump motor is having trouble starting and then the start and washing L.E.D.'s begin blinking which in turn interrupts the cycle. The only way to get it over the hump is to cancel the wash and start over. After about 3 or 4 restarts, it finally gets going. I will purchase a service manual if necessary but first off I would like to know how to power up the system into its diagnostic mode and then test the pump motor. As the dishwasher has been running for about 10 minutes now, the pump motor seems to be be starting and stopping quite often (maybe that's normal?), then I can hear the water draining. The cycle is still continuing with the Heavy, Start, and Washing, L.E.D.'s lit up continuously.  From my past experiences with this intermittent problem, once the wash cycle gets going, it will run all the way until the end and the dishes are clean.

Troubleshooting suggestions would be most appreciated.

Thanks in advance for your reply.

[Vance R]

The tech sheet should be in the toeplate envelope. This is just the basic - do the following while in standby:  Press any 3 keys in the sequence 1-2-3-1-2-3- 1-2-3 with no more than 1 second between keys to enter diagnostic mode.

[mrfixiter]

Hi Vance

Embarrassingly enough, I forgot there was a toeplate even though once I saw it at the bottom of the dishwasher, I remember having to remove it to check for leaks at one time or another. Anyway, I removed the toeplate and found an empty cellophane bag. Long story short, I found the service information stored away in my file cabinet.

I have some questions about initializing the diagnostic mode: When you (and also the tech sheet) say, press any 3 keys in the sequence 1-2-3, does that mean that any key I press initially is assigned to key #1 an so forth for the next two keys? In other words if I press, #1: Hi-Temp, #2: Sani-Rinse, #3: Hour Delay, are those choices now identified as the 1-2-3 sequence?

On another note, I opened the control board to perform a visual inspection of the components and the pc traces. I noticed an electrolytic capacitor had developed signs of outgassing. I removed it and tested it with an ESR meter to confirm my diagnosis. It was bad so I replaced it however before I pat myself on the back, I'm waiting for the dishwasher to fill up with more dishes so I can run another load and see if to works on the first try. I'll check back in a few days and let you know the results.

Thanks for your help.

mrfixiter

[Vance R]

25 minutes ago, mrfixiter said:

In other words if I press, #1: Hi-Temp, #2: Sani-Rinse, #3: Hour Delay, are those choices now identified as the 1-2-3 sequence?

Yes 

Once in the diag mode record the error codes and then make sure to clear the codes as in step 20. If there is a heater error the board will disable the heater until the error is cleared.

Edited January 28, 2023 by Vance R
add last sentences

[mrfixiter]

Great! Thank you.

mrfixiter

[mrfixiter]

I tried the three, quick, button presses as indicated in the tech sheet: 1-2-3, 1-2-3, 1-2-3. Each light illuminated as I was going through the sequence however when I completed the third sequence, just the remaining, final key press was lit. Aren't all the lights supposed to come on? I tried it with the door open and the door closed. It didn't matter. By the way, I would just like to begin with the error code history because the instructions say running a diagnostic cycle will erase all the history. Final question for now, does unplugging the dishwasher from AC power clear the error history?

Thanks for your reply.

mrfixiter

[Vance R]

49 minutes ago, mrfixiter said:

Aren't all the lights supposed to come on?

When all button pushes have been completed correctly and you have entered the diagnostic mode all the lights on the user interface will light up.  Common pitfalls - need to start with the power off washer must be in stand by mode, nice firm press on each button with no more than 1 second between press, do not pay attention the the lights until all 9 press have been completed.

 

55 minutes ago, mrfixiter said:

Final question for now, does unplugging the dishwasher from AC power clear the error history?

Nope

[mrfixiter]

I repeated the procedure. This time I pressed the buttons as fast as I could and that seemed to be the difference. The blink codes showed an error of 8-2 which according the tech sheet is a drain motor electrical problem (see list below). I have added my comments in the parenthesis.

• Loose connection in drain motor. (That doesn't seem very likely to me because if it were loose, it would be unlikely that the loose connection would become functional for the entire wash/drain cycle).
• Open fuse on control to drain motor. (Not possible because the problem is intermittent so that eliminates a blown fuse).
• Faulty drain motor circuit on the control (This seems the most likely).

Looking at the history of the dishwasher since it was new in 2012, I had to replace the drain pump  in 2017 because the  machine wasn't draining and water was spilling out of the washer. Now six years later, it looks like it may be failing again however this time (if my memory serves me correctly) the washer isn't shutting itself off and no water is accumulating in the tub.

Getting back to retrieving the error code history, if the same fault code keeps happening, does the microprocessor append it to the existing error log or is it not recorded? The reason I ask is that there was only one error code stored in the system.

Thanks for your reply.

mrfixiter

[Vance R]

1 minute ago, mrfixiter said:

does the microprocessor append it to the existing error log or is it not recorded?

Yes it stores 4 error codes. In step 21 you can clear the codes, which is recommended. This way you can see if they come back. 

[mrfixiter]

My point was that if you repeatedly restart the dishwasher after it repeatedly shuts down, as it has in my case, will the error log show, 8-2, 8-2, 8-2, 8-2? Because I am seeing only one error code displayed unless I'm not following the directions correctly. I did notice that the Hi-Temp button clears the history after all the errors are displayed. Does that imply that if I don't press the Hi-Temp button at that particular point, then the diagnostics mode will continue without clearing the codes?

As a precautionary measure, I'm going to remove the drain pump and bench test it to see if runs smoothly. When it failed six years ago, it wasn't running smoothly at all.

Thanks for your reply.

mrfixiter

[Vance R]

16 hours ago, mrfixiter said:

then the diagnostics mode will continue without clearing the codes?

Yes

[mrfixiter]

Hi Vance,

I did not clear out the codes so I was still wondering about my earlier question:

On 1/29/2023 at 7:16 PM, mrfixiter said:

Getting back to retrieving the error code history, if the same fault code keeps happening, does the microprocessor append it to the existing error log or is it not recorded? The reason I ask is that there was only one error code stored in the system ( EDIT: after many malfunctions)

Instead of bench testing the drain pump, I decided to run a small load of dishes in the normal cycle to see what would happen. It ran without a glitch on the first attempt. It hadn't done that for the past four or five loads. Time will tell if replacing the cap was more than a temporary solution.

Here is the description of the bad cap on the control board. The value is 1,000 µF 6.3 Volt, 105°C, and its reference number is C48. Below are some photos. If you inspect your control board and find that C48 is bulging and you want to replace it, you're going to need to acquire a temperature controlled soldering iron and use a generous amount of flux because it takes A LOT of heat (up to 400° C) to melt the solder on this multilayered PC board. Proceed with caution and do not lift out the capacitor until the solder is flowing well or you may damage the PC pads and/or traces.

mrfixiter

 

[mrfixiter]

More than a month has passed and everything is back to normal after replacing the capacitor. There are no more blinking lights interrupting the cycle.

Thanks for your assistance.

mrfixiter